Absorbent article

ABSTRACT

The present invention addresses the problem of providing an absorbent article that has an improved ability to transfer menstrual blood from a liquid-permeable layer to an absorbent body and can reduce the amount of the menstrual blood remaining in the liquid-permeable layer. To solve this problem, provided is a sanitary napkin provided with a top sheet, a back sheet and an absorbent body that is interposed between the top sheet and the back sheet, wherein convex portions formed in an excretion orifice contact region of the top sheet are coated with a blood lubricity-imparting agent that has a kinetic viscosity of 0.01-80 mm 2 /s at 40° C., a water retention rate of 0.01-4.0 mass % and a weight-average molecular weight of less than 1,000.

TECHNICAL FIELD

The present invention relates to an absorbent article.

BACKGROUND ART

In an absorbent article, such as a sanitary napkin or panty liner,liquid excreta, such as menstrual blood penetrates the liquid-permeablelayer, such as the top sheet, and is absorbed and retained by theabsorbent body, but due to the high viscosity of menstrual blood ittends to remain in the liquid-permeable layer. When menstrual bloodremains in the liquid-permeable layer of an absorbent article, itproduces a feeling of stickiness and visual discomfort for the wearer,and it has therefore been a goal to improve the migration of menstrualblood from the liquid-permeable layer to the absorbent body and reduceresidual menstrual blood in the liquid-permeable layer.

On the other hand, absorbent articles coated with a lotion compositionon the top sheet are known in the prior art (PTLs 1 and 2). In PTL 1, apolypropylene glycol material-containing lotion composition is coatedonto the inner surface of a top sheet (the clothing side surface), theinner surface of the back sheet (the body side surface), and on the basematerial between the inner surface of the top sheet and the innersurface of the back sheet, while in PTL 2, a polypropylene glycolmaterial-containing lotion composition is coated onto the outer surfaceof a top sheet (the body side surface).

Top sheets having an irregular structure on the surface are also knownin the prior art (PTLs 3 to 5). In PTLs 3 to 5, heat treatment iscarried out on a laminated sheet having a non-heat-shrinkable fiberlayer on the skin contact surface side, and having a heat-shrinkablefiber layer on the non-skin contact surface side, which is partiallybonded to the non-heat-shrinkable fiber layer by a joining section, andby causing the non-heat-shrinkable fiber layer to bulge on the skincontact surface side by heat shrinkage of the heat-shrinkable fiberlayer, an irregular structure is formed on the surface of the top sheet.

CITATION LIST Patent Literature PTL 1 Japanese Unexamined PatentPublication No. 2010-518918 PTL 2 Japanese Unexamined Patent PublicationNo. 2011-510801 PTL 3 Japanese Unexamined Patent Publication No.2002-187228 PTL 4 Japanese Unexamined Patent Publication No. 2003-247155PTL 5 Japanese Unexamined Patent Publication No. 2007-177340 SUMMARY OFINVENTION Technical Problem

In PTLs 1 to 5, however, the design is not, such as to improve migrationof menstrual blood from the liquid-permeable layer, such as the topsheet, to the absorbent body, and reduce residue of menstrual blood inthe liquid-permeable layer.

It is therefore an object of the present invention to provide anabsorbent article having improved migration of menstrual blood from theliquid-permeable layer to the absorbent body, and reduced residue ofmenstrual blood in the liquid-permeable layer.

Solution to Problem

In order to solve the problems described above, the invention providesan absorbent article comprising a liquid-permeable layer, aliquid-impermeable layer and an absorbent body situated between theliquid-permeable layer and the liquid-impermeable layer, wherein theliquid-permeable layer has a first layer with a skin contact surface anda non-skin contact surface and a second layer situated on the non-skincontact surface side of the first layer, the second layer is a layerformed by heat shrinkage of a heat-shrinkable fiber layer and the firstlayer is a layer formed by deformation of a non-heat-shrinkable fiberlayer which is partially joined to the heat-shrinkable fiber layer by ajoining section, by heat shrinkage of the heat-shrinkable fiber layer, aprojection bulges out on the skin contact surface side, produced bydeformation of the non-heat-shrinkable fiber layer, are formed at leastin the excretory opening contact region on the skin contact surface, andat least the projection of the excretory opening contact region iscoated with a blood slipping agent having a 40° C. kinematic viscosityof 0.01 to 80 mm²/s, a water holding percentage of 0.01 to 4.0 mass %and a weight-average molecular weight of less than 1,000.

In the absorbent article of the invention, menstrual blood excreted bythe wearer and reaching the excretory opening contact region slips downtogether with the blood slipping agent present in the projections, andmigrates through the liquid-permeable layer into the absorbent body. Theabsorbent article of the invention therefore has improved migration ofmenstrual blood from the liquid-permeable layer to the absorbent body,and reduced residue of menstrual blood in the liquid-permeable layer.This prevents the skin contact surface of the liquid-permeable layerfrom having a sticky feel, and maintains a smooth feel. This functionand effect of the blood slipping agent is exhibited regardless ofchanges in menstrual blood discharge during menstruation (that is,whether the amount of discharged menstrual blood is large or small).

Advantageous Effects of Invention

According to the invention there is provided an absorbent article thatcan improve migration of menstrual blood from the liquid-permeable layerto the absorbent body, and reduce residue of menstrual blood in theliquid-permeable layer.

BRIEF DESCRIPTION OF DRAWING

FIG. 1 is a partial cutaway plan view of a sanitary napkin according toone embodiment of the absorbent article of the invention.

FIG. 2 is a cross-sectional view of FIG. 1 along line A-A.

FIG. 3 is a partial perspective view of the top sheet of the sanitarynapkin shown in FIG. 1.

FIG. 4 is a partial magnified cross-sectional view showing the processby which a top sheet is produced by heat shrinkage treatment.

FIG. 5 is a diagram illustrating a method for producing a sanitarynapkin.

FIG. 6 is an electron micrograph of the skin contact surface of a topsheet in a sanitary napkin wherein the top sheet comprises tri-C2L oilfatty acid glycerides.

FIG. 7 is a pair of photomicrographs of menstrual blood containing andnot containing a blood slipping agent.

FIG. 8 is a diagram illustrating a method of measuring surface tension.

FIG. 9 is a partial enlarged plan view of the embossing roll used inTest Example 8.

DESCRIPTION OF EMBODIMENTS

The absorbent article of the invention will now be described.

The absorbent article according to aspect 1 comprises a liquid-permeablelayer, a liquid-impermeable layer and an absorbent body situated betweenthe liquid-permeable layer and the liquid-impermeable layer, wherein theliquid-permeable layer has a first layer with a skin contact surface anda non-skin contact surface and a second layer situated on the non-skincontact surface side of the first layer, the second layer is a layerformed by heat shrinkage of a heat-shrinkable fiber layer and the firstlayer is a layer formed by deformation of a non-heat-shrinkable fiberlayer which is partially joined to the heat-shrinkable fiber layer by ajoining section, by heat shrinkage of the heat-shrinkable fiber layer, aprojection bulges out on the skin contact surface side, produced bydeformation of the non-heat-shrinkable fiber layer, are formed at leastin the excretory opening contact region on the skin contact surface, andat least the projection of the excretory opening contact region arecoated with a blood slipping agent having a 40° C. kinematic viscosityof 0.01 to 80 mm²/s, a water holding percentage of 0.01 to 4.0 mass %and a weight-average molecular weight of less than 1,000.

For the purpose of the absorbent article of the invention, the term“heat-shrinkable fiber” is used in a sense encompassing not only fiberswhose actual fiber lengths are shortened by heat treatment but alsofibers whose actual fiber lengths are not shortened but whose apparentfiber lengths are shortened by heat treatment (for example, latentcrimping fibers whose apparent fiber lengths are shortened by crimpdevelopment), and the term “non-heat-shrinkable fibers” is used in asense encompassing not only fibers that essentially have no heatshrinking property but also fibers that have a heat shrinking propertybut whose heat shrinkage initiation temperature is higher than the heatshrinkage initiation temperature of the heat-shrinkable fibers in theheat-shrinkable fiber layer (that is, fibers that essential do notundergo heat shrinkage at a temperature below the heat shrinkageinitiation temperature of the heat-shrinkable fibers in theheat-shrinkable fiber layer).

In a preferred aspect (aspect 2) of the absorbent article of aspect 1,the density of the second layer is higher than the density of the firstlayer. Migration of menstrual blood from the first layer to the secondlayer is improved by aspect 2.

In a preferred aspect (aspect 3) of the absorbent article of aspect 2,the density of the second layer is 0.1 g/cm³ or less. According toaspect 3, the function and effect of the blood slipping agent areeffectively exhibited without being inhibited by the second layer.

In a preferred aspect (aspect 4) of the absorbent article of aspect 2 or3, the density of the first layer is 0.05 g/cm³ or less. According toaspect 4, the function and effect of the blood slipping agent areeffectively exhibited without being inhibited by the first layer.

In a preferred aspect (aspect 5) of the absorbent article according toany of aspects 1 to 4, the joining section is a compressed section inwhich the non-heat-shrinkable fiber layer and heat-shrinkable fiberlayer are integrated in the thickness direction. According to aspect 5,the excretory opening contact region serves as the irregular structure,and therefore the function and effect of the blood slipping agent areeffectively exhibited.

In a preferred aspect (aspect 6) of the absorbent article according toany of aspects 1 to 5, the IOB of the blood slipping agent is 0.00 to0.60.

In an aspect (aspect 7) of the absorbent article according to any ofaspects 1 to 6, the blood slipping agent is selected from the groupconsisting of the following following items (i)-(iii), and anycombination thereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety, and (iii-3) one or more, same ordifferent groups selected from the group consisting of carboxyl group(—COOH) and hydroxyl group (—OH) substituting a hydrogen of thehydrocarbon moiety;

with the proviso that when 2 or more oxy groups are inserted in thecompound of (ii) or (iii), the oxy groups are not adjacent.

In a preferred aspect (aspect 8) of the absorbent article of any ofaspects 1 to 7, the blood slipping agent is selected from the groupconsisting of the following items (i′)-(iii′), and any combinationthereof:

(i′) a hydrocarbon;

(ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety; and

(iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety, and (iii′-3) one or more, same or different groups selected fromthe group consisting of carboxyl group (—COOH) and hydroxyl group (—OH)substituting a hydrogen on the hydrocarbon moiety;

with the proviso that when 2 or more same or different bonds areinserted in the compound of (ii′) or (iii′), the bonds are not adjacent.

In a preferred aspect (aspect 9) of the absorbent article according toany of aspects 1 to 8, the blood slipping agent is selected from thegroup consisting of the following items (A)-(F), and any combinationthereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety and (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of an ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—) inserted between a C—Csingle bond of the chain hydrocarbon moiety;

(E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl etherthereof; and

(F) a chain hydrocarbon.

In a preferred aspect (aspect 10) of the absorbent article according toany of aspects 1 to 9, the blood slipping agent is selected from thegroup consisting of (a₁) an ester of a chain hydrocarbon tetraol and atleast one fatty acid, (a₂) an ester of a chain hydrocarbon triol and atleast one fatty acid, (a₃) an ester of a chain hydrocarbon diol and atleast one fatty acid, (b₁) an ether of a chain hydrocarbon tetraol andat least one aliphatic monohydric alcohol, (b₂) an ether of a chainhydrocarbon triol and at least one aliphatic monohydric alcohol, (b₃) anether of a chain hydrocarbon diol and at least one aliphatic monohydricalcohol, (c₁) an ester of a chain hydrocarbon tetracarboxylic acid,hydroxy acid, alkoxy acid or oxoacid with 4 carboxyl groups, and atleast one aliphatic monohydric alcohol, (c₂) an ester of a chainhydrocarbon tricarboxylic acid, hydroxy acid, alkoxy acid or oxoacidwith 3 carboxyl groups, and at least one aliphatic monohydric alcohol,(c₃) an ester of a chain hydrocarbon dicarboxylic acid, hydroxy acid,alkoxy acid or oxoacid with 2 carboxyl groups, and at least onealiphatic monohydric alcohol, (d₁) an ether of an aliphatic monohydricalcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃)an ester of a fatty acid and an aliphatic monohydric alcohol, (d₄) adialkyl carbonate, (e₁) a polyoxy C₃-C₆ alkylene glycol, (e₂) an esterof a polyoxy C₃-C₆ alkylene glycol and at least one fatty acid, (e₃) anether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphaticmonohydric alcohol, and (f₁) a chain alkane, and any combinationthereof.

In a preferred aspect (aspect 11) of the absorbent article of any ofaspects 1 to 10, the blood slipping agent has a vapor pressure of 0.00to 0.01 Pa at 1 atmosphere, 40° C.

Two or more aspects of the absorbent article of the invention may alsobe combined.

There are no particular restrictions on the type and usage of theabsorbent article of the invention. For example, absorbent articlesinclude sanitary products and sanitary articles, such as sanitarynapkins and panty liners, which may be for humans or animals other thanhumans, such as pets. The liquid to be absorbed by the absorbent articleis not particularly restricted, but will mainly be liquid excreta, suchas menstrual blood.

Embodiments of the absorbent article of the invention will now bedescribed, using a sanitary napkin as an example, with reference to theaccompanying drawings.

As shown in FIG. 1 and FIG. 2, the sanitary napkin 1 according to oneembodiment of the absorbent article of the invention comprises aliquid-permeable top sheet 2, a liquid-impermeable back sheet 3, and anabsorbent body 4 formed between the top sheet 2 and the back sheet 3.

In FIG. 1, the X-axial direction is the widthwise direction of thesanitary napkin 1, the Y-axial direction is the lengthwise direction ofthe sanitary napkin 1, and the direction of the plane extending in theX-axial and Y-axial directions corresponds to the planar direction ofthe sanitary napkin 1. The same applies to the other drawings as well.

The sanitary napkin 1 is worn to absorb liquid excreta, such asmenstrual blood. It is worn in such a manner that the top sheet 2 is onthe skin side of the wearer, and the back sheet 3 is located on the sideof the clothing (underwear) of the wearer. Liquid excreta, such asmenstrual blood permeates the top sheet 2 and reaches the absorbent body4, and is absorbed and retained in the absorbent body 4. Leakage ofliquid excreta that has been absorbed and retained in the absorbent body4 is prevented by the back sheet 3.

As shown in FIG. 1, the top sheet 2 and back sheet 3 have their edgesbonded together in the lengthwise direction by seal sections 11 a, 11 b,forming the body section 6, while having their edges bonded together inthe widthwise direction by seal sections 12 a, 12 b, forming essentiallyrectangular wing sections 7 a, 7 b that extend out in the widthwisedirection from the body section 6.

The shape of the body section 6 can be appropriately adjusted in a rangesuited to the body of the wearer and to underwear, examples of shapesfor the body section 6 including essentially rectangular, essentiallyelliptical and essentially gourd-like shapes. The dimensions in thelengthwise direction of the body section 6 will usually be 100 to 500 mmand preferably 150 to 350 mm, while the dimensions in the widthwisedirection of the body section 6 will usually be 30 to 200 mm andpreferably 40 to 180 mm.

The bonding method for the seal sections 11 a, 11 b, 12 a, 12 b may beembossing, ultrasonic waves or a hot-melt adhesive. In order to increasethe bonding strength, two or more different bonding methods may becombined (for example, bonding with a hot-melt adhesive followed byembossing).

As an example of embossing, the top sheet 2 and back sheet 3 may bepassed together between a patterned embossing roll, with patternedprojections, and a flat roll, for embossing (a method known as roundsealing). By heating the embossing roll and/or flat roll by this method,each sheet is softened so that the seal sections become more distinct.Examples of emboss patterns include lattice-like patterns, zigzagpatterns and wavy patterns.

Examples of hot-melt adhesives include pressure-sensitive adhesives andheat-sensitive adhesives composed mainly of rubber-based compounds, suchas styrene-ethylene-butadiene-styrene (SEBS), styrene-butadiene-styrene(SBS) or styrene-isoprene-styrene (SIS), or composed mainly ofolefin-based compounds, such as linear low-density polyethylene; andwater-sensitive adhesives comprising water-soluble polymers (such aspolyvinyl alcohol, carboxylmethyl cellulose and gelatin) orwater-swelling polymers (such as polyvinyl acetate and sodiumpolyacrylate). Examples of adhesive coating methods include spiralcoating application, coater application, curtain coater application andsummit-gun coating.

As shown in FIG. 2, pressure-sensitive adhesive sections 13 a, 13 b areprovided on the clothing side of the back sheet 3 forming the wingsections 7 a, 7 b, and a pressure-sensitive adhesive section 13 c isprovided on the clothing side of the back sheet 3 forming the bodysection 6. The pressure-sensitive adhesive section 13 c is attached tothe crotch section of underwear, while the wing sections 7 a, 7 b arefolded toward the outer wall of the underwear and the pressure-sensitiveadhesive sections 13 a, 13 b are attached to the crotch section of theunderwear, thereby stably anchoring the sanitary napkin 1 to theunderwear.

Examples of pressure-sensitive adhesives to be used in thepressure-sensitive adhesive sections 13 a, 13 b, 13 c includestyrene-based polymers, such as styrene-ethylene-butylene-styrene blockcopolymer, styrene-butylene polymer, styrene-butylene-styrene blockcopolymer and styrene-isobutylene-styrene copolymer; tackifiers, such asC5 petroleum resins, C9 petroleum resins, dicyclopentadiene-basedpetroleum resins, rosin-based petroleum resins, polyterpene resins andterpenephenol resins; monomer plasticizers, such as tricresyl phosphate,dibutyl phthalate and dioctyl phthalate; and polymer plasticizers, suchas vinyl polymer and polyester.

The top sheet 2 is a sheet that allows permeation of liquid excreta,such as menstrual blood, an example thereof being a liquid-permeablelayer. As shown in FIG. 2 and FIG. 3, a plurality of projections 8 andrecesses 9 are formed on the skin contact surface of the top sheet 2(the top side in FIG. 2 and FIG. 3). Also, as shown in FIG. 3, the topsheet 2 has a first layer 21 and a second layer 22, but the top sheet 2is shown in a more simplified manner in FIG. 2, omitting the first layer21 and the second layer 22.

For this embodiment, projections 8 are formed over essentially theentire absorbent body placement region that includes the excretoryopening contact region 20 on the skin contact surface of the top sheet2, it being sufficient for the projections 8 to be formed in at leastthe excretory opening contact region 20 on the skin contact surface ofthe top sheet 2. The absorbent body placement region is the region inwhich the absorbent body 4 overlaps the top sheet 2 when the absorbentbody 4 has been projected onto the top sheet 2.

The excretory opening contact region 20 is the region in which theexcretory opening of the wearer (for example, the labia minora, labiamajora, etc.) contact when the sanitary napkin 1 is worn. The excretoryopening contact region 20 is the region delineated by the dotted line inFIG. 1, and it is set at essentially the center of the absorbent bodyplacement region. The location and area of the excretory opening contactregion 20 may be adjusted as appropriate. The excretory opening contactregion 20 may be set to be essentially the same region as the regionthat actually contacts with the excretory opening, or it may be set as alarger region, but from the viewpoint of preventing leakage of liquidexcreta, such as menstrual blood to the exterior, it is preferably setas a region larger than the region that actually contacts with theexcretory opening. The length of the excretory opening contact region 20will usually be 50 to 200 mm and is preferably 70 to 150 mm, and thewidth will usually be 10 to 80 mm and is preferably 20 to 50 mm.

For this embodiment, the excretory opening contact region 20 is set as avirtual region, but it may instead be set as a visually recognizableregion. Visual recognition may be produced by coloration of theexcretory opening contact region 20, or by formation of recesses aroundthe excretory opening contact region 20 (for example, recesses formed byheat embossing treatment).

While not shown here, essentially the entire excretory opening contactregion 20 is coated with a blood slipping agent having a 40° C.kinematic viscosity of 0.01 to 80 mm²/s, a water holding percentage of0.01 to 4.0 mass % and a weight-average molecular weight of less than1,000. The details regarding the blood slipping agent will be describedin a different section.

For this embodiment, essentially the entire excretory opening contactregion 20 is coated with the blood slipping agent, but it is sufficientto coat the blood slipping agent on at least the projections 8 of theexcretory opening contact region 20. So long as the blood slipping agentis coated on at least the projections 8 of the excretory opening contactregion 20, it may also be coated on sections other than the projections8 of the excretory opening contact region 20 (for example, the recesses9), or it may be coated in regions other than the excretory openingcontact region 20 on the skin contact surface (for example, the regionssurrounding the excretory opening contact region 20). For example, theblood slipping agent may be coated essentially over the entire skincontact surface or essentially over the entire absorbent body placementregion.

If the blood slipping agent is coated on at least the projections 8 ofthe excretory opening contact region 20, the following function andeffect will be exhibited. When menstrual blood excreted by the wearerreaches the excretory opening contact region 20, it slips together withthe blood slipping agent present in the projections 8 down into therecesses 9, and migrates through the top sheet 2 into the absorbent body4. Therefore, the sanitary napkin 1 has improved migration of menstrualblood from the top sheet 2 to the absorbent body 4, and can reduceresidue of menstrual blood in the top sheet 2. This prevents the skincontact surface of the top sheet 2 from having a sticky feel, andmaintains a smooth feel. This function and effect of the blood slippingagent is exhibited regardless of changes in menstrual blood dischargeduring menstruation (that is, whether the amount of discharged menstrualblood is large or small).

Since this embodiment has projections 8 and recesses 9 in the excretoryopening contact region 20 such that the excretory opening contact region20 has an irregular structure, the function and effect of the bloodslipping agent is effectively exhibited. The function and effect of theblood slipping agent can be reinforced by coating the blood slippingagent on the recesses 9 in addition to the projections 8.

Incidentally, since the blood slipping agent functions as a lubricatingagent to reduce friction between fibers, it can improve the flexibilityof the top sheet 2 as a whole.

The sanitary napkin 1 does not require components, such as emollientsand immobilizing agents, unlike in known absorbent articles containingskin care compositions, lotion compositions and the like, and the bloodslipping agent alone may be applied to the top sheet 2.

The basis weight of the blood slipping agent may usually be about 1 to30 g/m², preferably about 2 to 20 g/m² and even more preferably about 3to 10 g/m². If the basis weight of the blood slipping agent is lowerthan about 1 g/m², menstrual blood will tend to remain in the top sheet2, while if the basis weight of the blood slipping agent is greater thanabout 30 g/m², there will tend to be an increase in the sticky feelduring wear.

The basis weight of the blood slipping agent can be measured in thefollowing manner, for example.

(1) The region of the top sheet that is to be measured is cut out usinga sharp blade, such as a cutter replacement blade, while minimizing anyalteration in thickness, to obtain a sample.

(2) The area of the sample: SA (m²) and the mass: SM₀ (g) are measured.

(3) The sample is stirred for at least 3 minutes in a solvent that candissolve the blood slipping agent, such as ethanol or acetone, todissolve the blood slipping agent in the solvent.

(4) The sample is filtered on mass-measured filter paper, and the sampleis thoroughly rinsed with the solvent on the filter paper. The sample onthe filter paper is dried in an oven at 60° C.

(5) The masses of the filter paper and sample are measured, and the massof the filter paper is subtracted to calculate the dry sample mass: SM₁(g).

(6) The basis weight BBS (g/m²) of the blood slipping agent iscalculated by the following formula.

BBS(g/m²)=[SM ₀(g)−SM ₁(g)]/SA(m²)

In order to minimize error, multiple samples are taken from multipleabsorbent articles, without the total area of the sample exceeding 100cm², conducting several repeated measurements and taking the averagevalue.

The blood slipping agent is preferably coated without obstructing thevoids between the fibers of the top sheet 2. For example, the bloodslipping agent may be adhering as droplets or particulates on thesurfaces of the fibers of the top sheet 2, or covering the surfaces ofthe fibers.

The blood slipping agent is preferably coated so that the surface areais increased. This will increase the contact area between the bloodslipping agent and the menstrual blood and facilitate slipping of theblood slipping agent together with the menstrual blood. When the bloodslipping agent is present as droplets or particulates, the particlediameters can be reduced to increase the surface area.

Examples of methods for coating the blood slipping agent include methodsthat employ coating applicators (for example, non-contact coaters, suchas spiral coaters, curtain coaters, spray coaters and dip coaters. andcontact coaters). Non-contact coaters are preferred coating applicators.This will allow the droplets or particulate blood slipping agent toevenly disperse over the entirety, while reducing damage to the topsheet 2.

The blood slipping agent may, if desired, be applied as a coatingsolution containing a volatile solvent, such as an alcohol-basedsolvent, ester-based solvent or aromatic solvent. If the coatingsolution includes a volatile solvent, the viscosity of the coatingsolution containing the blood slipping agent will be lowered, therebyallowing the application steps to be simplified, facilitatingapplication and making heating during application unnecessary.

The blood slipping agent may be coated directly, if it is a liquid atroom temperature, or it may be heated to lower the viscosity, and whenit is a solid at room temperature, it may be heated to liquefaction andcoated with a control seam HMA (Hot Melt Adhesive) gun. By increasingthe air pressure of the control seam HMA gun, it is possible to coat theblood slipping agent as fine particulates. The coating amount of theblood slipping agent can be adjusted, for example, by adjusting thedischarged amount from a control seam HMA gun.

The blood slipping agent may be coated during production of the topsheet 2, or it may be coated in the manufacturing line for the sanitarynapkin 1. From the viewpoint of minimizing equipment investment, theblood slipping agent is preferably coated in the manufacturing line forthe sanitary napkin 1, and in order to prevent shedding of the bloodslipping agent which may contaminate the line, the blood slipping agentor its composition is preferably coated during a step downstream fromthe manufacturing line, and specifically, immediately beforeencapsulation of the product in an individual package.

As shown in FIG. 3 and FIG. 4, the top sheet 2 has a first layer 21having a skin contact surface and a non-skin contact surface, and asecond layer 22 provided on the non-skin contact surface side of thefirst layer 21.

One side of the first layer 21 (the top side in FIG. 3 and FIG. 4) isthe skin contact surface, and the other side (the bottom side in FIG. 3and FIG. 4) is the non-skin contact surface. As shown in FIG. 3 and FIG.4, a second layer 22 is layered on the non-skin contact surface of thefirst layer 21, so that the top sheet 2 has a two-layer structure. Thetop sheet 2 may also have one or more third layers in addition to thefirst layer 21 and the second layer 22. So long as the second layer 22is provided on the non-skin contact surface side of the first layer 21,there are no particular restrictions on the location where the thirdlayer is provided. For example, one or more third layers may be providedbetween the first layer 21 and the second layer 22. Alternatively, oneor more third layers may be provided on the side of the second layer 22opposite the first layer 21 side. The third layer may be anon-heat-shrinkable fiber layer or a heat-shrinkable fiber layer.Furthermore, so long as it does not interfere with deformation of thenon-heat-shrinkable fiber layer 21′ that occurs with heat shrinkage ofthe heat-shrinkable fiber layer 22′ (especially bulging to the skincontact surface side), the third layer may have another layer inaddition to the fiber layer (for example, an adhesive layer).

As shown in FIG. 4, the top sheet 2 is produced by heat treatment of alaminated sheet 2′ having a non-heat-shrinkable fiber layer 21′, aheat-shrinkable fiber layer 22′ and compressed sections 5′ thatpartially bond the non-heat-shrinkable fiber layer 21′ andheat-shrinkable fiber layer 22′, wherein the non-heat-shrinkable fiberlayer 21′ and heat-shrinkable fiber layer 22′ after heat treatmentcorrespond to the first layer 21 and the second layer 22, respectively.

As shown in FIG. 5, the laminated sheet 2′ can be produced by laminatingthe non-heat-shrinkable fiber layer 21′ and heat-shrinkable fiber layer22′ produced by prescribed methods, as the upper layer and lower layer,respectively, and then passing them between the upper roll 221 and lowerroll 222 of an embossing apparatus 220.

The non-heat-shrinkable fiber layer 21′ is a layer comprising one ormore non-heat-shrinkable fibers. The non-heat-shrinkable fibers may befibers having essentially no heat shrinking property, or they may befibers having a heat shrinking property but having a heat shrinkageinitiation temperature that is higher than the heat shrinkage initiationtemperature of the heat-shrinkable fibers in the heat-shrinkable fiberlayer 22′ (that is, fibers that essentially do not undergo heatshrinkage at a temperature below the heat shrinkage initiationtemperature of the heat-shrinkable fibers in the heat-shrinkable fiberlayer 22′).

Examples of non-heat-shrinkable fibers include regenerated fibers, suchas rayon; semisynthetic fibers, such as acetate; natural fibers, such ascotton and wool; and thermoplastic resin fibers, such as polyolefins(for example, polyethylene and polypropylene), polyesters (for example,polyethylene terephthalate) and polyamides. Non-heat-shrinkable fibersmay also be core-sheath composite fibers or side-by-side compositefibers, composed of a combination of two or more different thermoplasticresins. For example, in the case of fibers containing a polyethyleneresin, and especially fibers containing a high-density polyethyleneresin (density: 0.92 to 0.97 g/cm³), it is possible to obtain a softerfeel. The size of the non-heat-shrinkable fibers can be adjusted to 0.5to 20 dtex (especially 1.0 to 10 dtex), for example.

The non-heat-shrinkable fiber layer 21′ may also contain other fibers inaddition to the non-heat-shrinkable fibers. Such other fibers may beheat-sealable fibers, for example. The non-heat-shrinkable fibers in thenon-heat-shrinkable fiber layer 21′ may also have a heat sealableproperty. The non-heat-shrinkable fiber layer 21′ may include a smallamount of heat-shrinkable fibers so long as they do not inhibitdeformation (especially bulging to the skin contact surface side) of thenon-heat-shrinkable fiber layer 21′ that occurs with heat shrinkage ofthe heat-shrinkable fiber layer 22′, but preferably it does not containheat-shrinkable fibers. When the non-heat-shrinkable fiber layer 21′contains other fibers, the content of the non-heat-shrinkable fibers maybe appropriately adjusted in consideration of formability, bulk andcompressive deformation of the projections 8, but it will usually be 50mass % or greater and preferably 70 to 90 mass % of thenon-heat-shrinkable fiber layer 21′.

From the viewpoint of increasing the concealing property of the topsheet 2, the non-heat-shrinkable fiber layer 21′ may also contain aninorganic filler, such as titanium oxide, barium sulfate or calciumcarbonate.

The thickness and basis weight of the non-heat-shrinkable fiber layer21′ may be appropriately adjusted in consideration of formability, bulkand compressive deformation of the projections 8, but the thickness willusually be 0.1 to 20 mm and preferably 0.2 to 10 mm, and the basisweight will usually be 3 to 60 g/m² and preferably 5 to 30 g/m².

The heat-shrinkable fiber layer 22′ is a layer comprising one or moreheat-shrinkable fibers. The heat-shrinkable fibers may be fibers whoseactual fiber lengths are shortened by heat treatment, or fibers whoseactual fiber lengths are not shortened but whose apparent fiber lengthsare shortened by heat treatment (for example, latent crimping fiberswherein developed zigzag, Ω-shaped or spiral-shaped crimping developssuch that the apparent fiber lengths are shortened).

Latent crimping fibers are preferred heat-shrinkable fibers. When theheat-shrinkable fiber layer 22′ contains latent crimping fibers, thesecond layer 22 will contain crimping fibers that have developed crimps,and therefore extensibility of the second layer 22 (especiallyextensibility in the planar direction) will increase.

Various types of latent crimping fibers are known (for example, JapaneseUnexamined Patent Publication HEI No. 9-296325, Japanese UnexaminedPatent Publication HEI No. 2-191720 and Japanese Unexamined PatentPublication No. 2007-177335), and they may be appropriately selected foruse. Examples of latent crimping fibers include eccentric core-sheathcomposite fibers or side-by-side composite fibers that comprise two ormore different types of thermoplastic resins with different shrinkagefactors. Examples of two different thermoplastic resins with differentshrinkage factors include a combination of ethylene-propylene randomcopolymer (EP) and polypropylene (PP), and a combination of acopolymerizable polyester composed mainly of polyethylene terephthalate,and polyethylene terephthalate (PET). For combinations of two differentthermoplastic resins with different shrinkage factors, examples ofresins with relatively high shrinkage factors (high shrinkage factorresins) include copolymers composed mainly of ethylene, or low-densitypolyethylene, where examples of copolymers composed mainly of ethyleneinclude ethylene-propylene copolymer, ethylene-butene-1-propyleneterpolymer, ethylene-vinyl acetate copolymer, ethylene-methyl acrylatecopolymer and ethylene-ethyl acrylate copolymer, and examples oflow-density polyethylene include low-density polyethylene and linearlow-density polyethylene, obtained by high-pressure polymerization.Examples of resins with relatively low shrinkage factors forcombinations of two different thermoplastic resins with differentshrinkage factors (low shrinkage factor resins) include polyolefin-basedresins, such as polypropylene and polyethylene, and polyester-basedresins, such as polyethylene terephthalate and polybutyleneterephthalate. The size of latent crimping fibers (size beforedevelopment of crimping) may be adjusted to 0.5 to 20 dtex (especially 1to 10 dtex), for example.

The heat-shrinkable fiber layer 22′ may also contain other fibers inaddition to the heat-shrinkable fibers. Examples for other fibersinclude heat-sealable fibers and non-heat-shrinkable fibers. Theheat-shrinkable fibers in the heat-shrinkable fiber layer 22′ may alsohave a heat sealable property. When the heat-shrinkable fiber layer 22′contains other fibers, the content of the heat-shrinkable fibers may beappropriately adjusted in consideration of formability, bulk andcompressive deformation of the projections 8, but it will usually be 50mass % or greater and preferably 70 to 90 mass % of the heat-shrinkablefiber layer 22′.

From the viewpoint of increasing the concealing property of the topsheet 2, the heat-shrinkable fiber layer 22′ may also contain aninorganic filler, such as titanium oxide, barium sulfate or calciumcarbonate.

The thickness and basis weight of the heat-shrinkable fiber layer 22′may be appropriately adjusted in consideration of formability, bulk andcompressive deformation of the projections 8, but the thickness willusually be 0.1 to 10 mm and preferably 0.2 to 20 mm, and the basisweight will usually be 8 to 100 g/m² and preferably 10 to 50 g/m².

Examples of heat-sealable fibers that may be contained in thenon-heat-shrinkable fiber layer 21′ and/or the heat-shrinkable fiberlayer 22′ include heat-sealable fibers composed of a thermoplasticresin, such as polyolefin, polyester or polyamide.

Examples of polyolefins include straight-chain low-density polyethylene(LLDPE), low-density polyethylene (LDPE), medium-density polyethylene(MDPE), high-density polyethylene (HDPE), polypropylene, polybutylene,and copolymers composed mainly of the foregoing (for example,ethylene-vinyl acetate copolymer (EVA), ethylene-ethyl acrylatecopolymer (EEA), ethylene-acrylic acid copolymer (EAA) or anethylene-propylene random copolymer (EP)). Polyethylene, and especiallyHDPE, is preferred from the viewpoint of thermal processing propertiessince it has a relatively low softening point of around 100° C., andalso has low rigidity and a pliable feel.

Examples of polyesters include polyesters of straight-chain or branchedpolyhydroxyalkane acids up to C20, such as polyethylene terephthalate(PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate(PBT), polylactic acid and polyglycolic acid, copolymers composed mainlythereof, and copolymerized polyesters composed mainly of alkyleneterephthalates copolymerized with a small amount of another component.PET is preferred from the viewpoint of its elastic repulsion whichallows formation of fibers and nonwoven fabrics with high cushioningproperties, as well as from an economical viewpoint, since it can becommercially obtained at low cost.

Examples of polyamides include 6-nylon and 6,6-nylon.

The heat-sealable fibers may be composed of a single type ofthermoplastic resin, or they may be composite fibers comprising two ormore thermoplastic resins (for example, core-sheath composite fibers orside-by-side composite fibers). Heat-sealable fibers may be short staplefibers or long filaments. The thicknesses of the heat-sealable fibersmay be adjusted to 1-7 dtex, for example.

The form of the fiber aggregates composing the non-heat-shrinkable fiberlayer 21′ and heat-shrinkable fiber layer 22′ may be a web formed by acarding method; a nonwoven fabric formed by a heat fusion method,hydroentangling method, needle punching method, solvent bonding method,spunbond method or meltblown method, or a knitted fabric or the like. Aweb formed by a carding method is the fiber aggregate prior to formationof a nonwoven fabric. Such a web is one that has not been subjected topost-treatment applied to a carded web in a nonwoven fabric productionprocess (for example, heat fusion treatment in an air-through method orcalender method), and has its fibers very loosely entangled.

The non-heat-shrinkable fiber layer 21′ is preferably a web formed by acarding method. This will improve the formability, bulk and compressivedeformation of the projections 8. When the non-heat-shrinkable fiberlayer 21′ is a web formed by a carding method, preferably theconstituent fibers of the non-heat-shrinkable fiber layer 21′ are bondedtogether (for example, bonded by heat fusion or with a solvent) orforcibly entangled, either during or after formation of the compressedsections 5′.

The compressed sections 5′ are recesses formed by heat embossingtreatment. Heat embossing treatment can be carried out using anembossing apparatus 220 as shown in FIG. 5. The embossing apparatus 220has an upper roll 221 provided with a plurality of projections (notshown) on the outer peripheral surface, and a lower roll 222 having asmooth outer peripheral surface. The plurality of projections of theupper roll 221 are formed to correspond to the shape and arrangementpattern for the compressed sections 5′, and the plurality of sections ofthe non-heat-shrinkable fiber layer 21′ which are mutually separated bythe projections, are heated while being compressed in the thicknessdirection of the non-heat-shrinkable fiber layer 21′. This results information of compressed sections 5′ where the non-heat-shrinkable fiberlayer 21′ and heat-shrinkable fiber layer 22′ are integrated in thethickness direction, which serve as recesses. The compressed sections 5′formed in this manner are compacted and have a smaller thickness andincreased density compared to the other sections of the laminated sheet2′.

When the non-heat-shrinkable fiber layer 21′ and/or heat-shrinkablefiber layer 22′ is to comprise heat-sealable fibers, melting andsolidification of the heat-sealable fibers during formation of thecompressed sections 5′ can cause heat fusion of the non-heat-shrinkablefiber layer 21′ and the heat-shrinkable fiber layer 22′. When theheat-sealable fibers are composite fibers, melting and solidification ofthe low-melting-point resin (for example, the resin of the sheathcomponent of core-sheath composite fibers) can cause heat fusion of thenon-heat-shrinkable fiber layer 21′ and the heat-shrinkable fiber layer22′.

The upper roll 221 and/or lower roll 222 may be heated in the embossingapparatus 220, allowing heating to be performed during compression. Theheating temperature for embossing treatment by the embossing apparatus220 will usually be 60° C. to 180° C. and is preferably 80° C. to 160°C., the pressure will usually be 10 to 3000 N/mm and is preferably 0.005to 2 N/mm, and the treatment time will usually be 0.0001 to 5 secondsand is preferably 0.005 to 2 seconds.

The heating temperature for embossing treatment may be at or above theheat shrinkage initiation temperature of the heat-shrinkable fibers inthe heat-shrinkable fiber layer 22′, or it may be below thattemperature.

When the heating temperature for embossing treatment is at or above theheat shrinkage initiation temperature of the heat-shrinkable fibers inthe heat-shrinkable fiber layer 22′, heat-sealable fibers having amelting point that is at or above the heat shrinkage initiationtemperature of the heat-shrinkable fibers may be included in thenon-heat-shrinkable fiber layer 21′ and/or heat-shrinkable fiber layer22′, forming compressed sections 5′ as heat-fused sections where bothlayers are integrated in the thickness direction. Since the heat-fusedsections do not melt by heat treatment, bonding of the two layers can bemaintained during heat treatment. When the heat-sealable fibers arecomposite fibers, the melting point of the heat-sealable fiber means themelting point of the low-melting-point resin.

When the heating temperature for embossing treatment is at or above theheat shrinkage initiation temperature of the heat-shrinkable fibers, itis preferred to minimize heat shrinkage of the heat-shrinkable fibers.Heat shrinkage can be minimized, for example, by heating with tensionapplied to the laminated sheet 2′, where tension is applied, forexample, by piercing and holding with a plurality of upward orientedpins provided on a pin tenter chain, directed from the lower side towardthe upper side of the laminated sheet 2′ (that is, from theheat-shrinkable fiber layer 22′ side toward the non-heat-shrinkablefiber layer 21′ side). The details regarding such methods of controllingheat shrinkage are described in Japanese Unexamined Patent PublicationNo. 2003-247155 and Japanese Unexamined Patent Publication No.2007-177340, for example.

When the heating temperature for embossing treatment is below the heatshrinkage initiation temperature of the heat-shrinkable fibers of theheat-shrinkable fibers, heat-sealable fibers having a melting point thatis below the heat shrinkage initiation temperature of theheat-shrinkable fibers may be included in the non-heat-shrinkable fiberlayer 21′ and/or heat-shrinkable fiber layer 22′, forming compressedsections 5′ as heat-fused sections where both layers are integrated inthe thickness direction. In this case there is no need to minimize heatshrinkage of the heat-shrinkable fibers, but there is a possibility thatthe heat-fused sections may melt by heat treatment.

The compressed sections 5′ are roughly circular shapes, when thelaminated sheet 2′ is viewed flat from the non-heat-shrinkable fiberlayer 21′ side, and are disposed in a zigzag lattice-like fashionthroughout. The compressed sections 5′ may also be shapes other thancircular shapes, such as ellipsoid, triangular, rectangular orpolygonal. The arrangement pattern of the compressed sections 5′ may bechanged as appropriate, and for example, they may be continuously formedin a linear fashion with straight lines, curves or the like.

The number and locations of the compressed sections 5′ may be adjustedas appropriate, in consideration of formability and bulk of theprojections 8. One region surrounded by a plurality of compressedsections 5′ (four compressed sections 5′ for this embodiment) on thenon-heat-shrinkable fiber layer 21′ bulges out toward the skin contactsurface side, starting from the compressed sections 5′, thus forming oneprojection 8. The number of compressed sections 5′ surrounding oneregion in which one projection 8 is formed will usually be 3 or more,and preferably 4 or more. The upper limit will usually be 12, and ispreferably 8.

A region in which one projection 8 is formed may be surrounded bycompressed sections 5′ continuously formed in a linear fashion bystraight lines, curves or the like. For example, when the compressedsections 5′ are formed in a mesh-like manner, the regions in theinterior area of each mesh cell bulge toward the skin contact surfaceside, forming one projection 8. In this case, the compressed sections 5′preferably encompass 10 to 100% and more preferably encompass 20-100% ofthe total surrounding area of the region in which each projection 8 isformed.

The compressed sections 5′ for this embodiment are examples of joiningsections that join the non-heat-shrinkable fiber layer 21′ and theheat-shrinkable fiber layer 22′. The joining sections that join thenon-heat-shrinkable fiber layer 21′ and the heat-shrinkable fiber layer22′ can be formed by a joining method other than heat embossingtreatment, such as ultrasonic embossing or bonding with an adhesive.

Heat shrinkage treatment of the laminated sheet 2′ can be carried out ina heat shrinkage treatment zone 170, such as shown in FIG. 5. A meshconveyor belt, pin tenter, clip tenter or the like may be used to conveythe laminated sheet 2′ to the heat shrinkage treatment zone 170. Whenthe laminated sheet 2′ is transported in the heat shrinkage treatmentzone 170, hot air heated to a temperature above the heat shrinkageinitiation temperature of the heat-shrinkable fiber in theheat-shrinkable fiber layer 22′ is blasted onto the laminated sheet 2′(with an air-through system, for example), and the heat-shrinkable fiberlayer 22′ undergoes heat shrinkage.

The heat shrinkage factor of the heat-shrinkable fiber layer 22′ may beappropriately adjusted in consideration of formability, bulk andcompressive deformation of the projections 8, but it will usually be 20%to 90% and is preferably 40% to 80%.

The heat shrinkage factor is calculated by the following formula.

Heat shrinkage factor=(S ₀ −S ₁)/S ₀×100

[In the formula, S₀ is the area of a reference region before heatshrinkage treatment, and S₁ is the area of the reference region afterheat shrinkage treatment.]

The heat shrinkage factor of the heat-shrinkable fiber layer 22′ can beappropriately adjusted by controlling the amount and type ofheat-shrinkable fibers in the heat-shrinkable fiber layer 22′, thetransport speed of the laminated sheet 2′, and the hot air temperatureand wind speed, and adjusting the tenter width.

During heat shrinkage treatment, the degree of friction force applied tothe laminated sheet 2′ is preferably lowered. When a mesh conveyor beltis to be used for transport of the laminated sheet 2′, hot air may beblasted from the back side of the mesh conveyor belt to reduce thepressing force on the mesh conveyor belt to zero or a negative value.Also, when a pin tenter or clip tenter is to be used for transport ofthe laminated sheet 2′, the laminated sheet 2′ may be in a free state.

Hot air blasting is merely an example of heat shrinkage treatment. Theheat shrinkage treatment is not particularly restricted so long as itallows heating to above the heat shrinkage initiation temperature of theheat-shrinkable fibers in the heat-shrinkable fiber layer 22′. The heatshrinkage treatment can be carried out using hot air, or another heatingmedium, such as microwaves, steam or infrared rays.

The heating temperature and heating time for heat shrinkage treatmentcan be appropriately adjusted based on the heat shrinkage initiationtemperature of the heat-shrinkable fibers. The heating temperature maybe set to 125° C. to 150° C., for example, and the heating time may beset to 1 to 20 seconds, for example. The details regarding such heattreatment are described in Japanese Unexamined Patent Publication No.2003-247155 and Japanese Unexamined Patent Publication No. 2007-177340,for example.

When the laminated sheet 2′ is subjected to heat shrinkage treatment, asshown in FIG. 4, the non-heat-shrinkable fiber layer 21′ deforms due toheat shrinkage of the heat-shrinkable fiber layer 22′. Specifically, oneregion surrounded by a plurality of compressed sections 5′ (fourcompressed sections 5′ for this embodiment) on the non-heat-shrinkablefiber layer 21′ bulges out toward the skin contact surface side,starting from the compressed sections 5′, as heat shrinkage of theheat-shrinkable fiber layer 22′ takes place, thus forming one projection8. Since numerous regions surrounded by a plurality of compressedsections 5′ (four compressed sections 5′ for this embodiment) arepresent in the non-heat-shrinkable fiber layer 21′, deformation of thenon-heat-shrinkable fiber layer 21′ results in formation of numerousprojections 8. Thus, numerous projections 8 are formed bulging to theskin contact surface side, produced by deformation of thenon-heat-shrinkable fiber layer 21′ at least in the excretory openingcontact region 20 of the skin contact surface.

When the non-heat-shrinkable fiber layer 21′ is a web formed by acarding method, the interiors of the projections 8 formed by heatshrinkage treatment are filled with the fibers composing the web, andthe fibers composing the web are oriented along the projections. On theother hand, when the non-heat-shrinkable fiber layer 21′ is in the formof a nonwoven fabric or knitted fabric, the interiors of the projections8 formed by heat shrinkage treatment become hollow.

The non-heat-shrinkable fiber layer 21′ and the heat-shrinkable fiberlayer 22′ after heat shrinkage treatment correspond to the first layer21 and second layer 22, respectively. The first layer 21 is a layer inwhich the non-heat-shrinkable fiber layer 21′ that has been partiallybonded with the heat-shrinkable fiber layer 22′ by the compressedsections 5′ is deformed by heat shrinkage of the heat-shrinkable fiberlayer 22′, and it contains non-heat-shrinkable fibers that essentiallydo not undergo heat shrinkage by heat treatment. The second layer 22 isa layer wherein the heat-shrinkable fiber layer 22′ has undergone heatshrinkage, and it contains heat-shrinkable fibers that have undergoneheat shrinkage, such as fibers whose actual fiber lengths have beenshortened by heat treatment (for example, fibers whose actual fiberlengths have been shortened by changes in resin crystal state), orfibers whose actual fiber lengths have not been shortened but whoseapparent fiber lengths have been shortened by heat treatment (forexample, crimping fibers wherein developed zigzag, Ω-shaped or spiral orother shaped crimping has developed such that the apparent fiber lengthshave been shortened).

The thickness and basis weight of the first layer 21 will vary dependingon the thickness and basis weight of the non-heat-shrinkable fiber layer21′ and the heat shrinkage factor of the heat-shrinkable fiber layer22′, but the thickness will usually be 0.2 to 10 mm and preferably 0.4to 2.5 mm, and the basis weight will usually be 5 to 100 g/m² andpreferably 10 to 50 g/m².

The thickness and basis weight of the second layer 22 will varydepending on the thickness, basis weight and heat shrinkage factor ofthe heat-shrinkable fiber layer 22′, but the thickness will usually be0.2 to 5 mm and is preferably 0.5 to 2.5 mm, and the basis weight willusually be 5 to 100 g/m² and is preferably 10 to 50 g/m².

The density of the second layer 22 is preferably greater than thedensity of the first layer 21. This can improve migration of menstrualblood from the first layer 21 to the second layer 22.

When the density of the second layer 22 is greater than the density ofthe first layer 21, the density of the second layer 22 is preferably 0.1g/cm² or less and more preferably 0.08 g/cm² or less. In this case, thefunction and effect of the blood slipping agent are effectivelyexhibited without being inhibited by the second layer 22. The lowerlimit for the density of the second layer 22 is preferably 0.04 g/cm²and more preferably 0.06 g/cm².

When the density of the second layer 22 is greater than the density ofthe first layer 21, the density of the first layer 21 is preferably 0.05g/cm² or less and more preferably 0.04 g/cm² or less. In this case, thefunction and effect of the blood slipping agent are effectivelyexhibited without being inhibited by the first layer 21. The lower limitfor the density of the first layer 21 is preferably 0.005 g/cm² and morepreferably 0.01 g/cm².

The densities of the first layer 21 and second layer 22 are calculatedby dividing the basis weights by the thicknesses.

The basis weight can be measured by the following method, for example.

(1) A mark is created in the region to be measured and the area: SA_(α)(m²) is measured. In order to minimize error, marking is made so thatthe total area of the sample exceeds 5 cm².

(2) The marked area is cut with a sharp blade, for example a cutterreplacement blade, and the total mass measured as TM (g).

(3) The basis weight BS_(α) (g/m²) of the area to be measured isdetermined by the following formula:

BS _(α)(g/m²)=TM(g)/SA _(α)(m²).

The thickness can be measured by the following method, for example.

Measurement is performed using a thickness gauge (FS-60DS by DaieiKagaku Seiki Mfg. Co., Ltd.), after pressing 5 different locations (φ44mm measuring plane) for 10 seconds with a measuring pressure of 3 g/cm²(constant pressure).

When the top sheet 2 has one or more third layers between the firstlayer 21 and the second layer 22, the density of the third layer ispreferably adjusted so that the density increases from the first layer21 toward the second layer 22. This can improve migration of menstrualblood from the first layer 21 to the second layer 22.

As shown in FIG. 4, the first layer 21 and the second layer 22 arepartially joined by compressed sections 5, corresponding to thecompressed sections 5′ after heat shrinkage treatment, and thecompressed sections 5 serve as recesses 9. The shapes and arrangementpattern of the compressed sections 5′ are not significantly alteredafter heat shrinkage treatment, the compressed sections 5 being roughlycircular when the top sheet 2 is viewed flat from the first layer 21side, and disposed in a zigzag lattice-like fashion throughout. The heatshrinkage treatment may slightly alter the shapes and structures of thecompressed sections 5′ in some cases. For example, it may causeshrinkage or melting solidification of the fibers composing thecompressed sections 5′ in some cases.

The ratio of the area of the compressed sections 5 with respect to thearea of the first layer 21 (the area ratio) will usually be 2.5 to 50%and is preferably 4 to 20%.

A plurality of open holes may also be provided in the top sheet 2. Thiswill increase the liquid permeability and reduce leakage and mustiness.The open holes can be formed by perforating the top sheet 2, forexample. The diameters of the open holes can be adjusted to 0.2 to 10mm, for example. When a plurality of open holes are formed, the spacingbetween the open holes may be adjusted to 0.5 to 20 mm, for example.

The top sheet 2 may also be subjected to hydrophilicizing treatment.Hydrophilicizing treatment may be, for example, coating of the surfaceof the top sheet 2 with a hydrophilic agent, or addition of ahydrophilic agent to the constituent components of the first layer 21and/or second layer 22, corona treatment, plasma treatment, or the like.When the top sheet 2 is subjected to hydrophilicizing treatment,lipophilic regions created by the blood slipping agent and hydrophilicregions created by the hydrophilic agent become sparsely dispersed inthe top sheet 2, so that menstrual blood will tend to slip from theprojections 8 of the top sheet 2 and migrate into the absorbent body.

The back sheet 3 is a sheet that prevents permeation of liquid excreta,such as menstrual blood, an example thereof being a liquid-impermeablelayer. The back sheet 3 can prevent leakage of absorbed liquid excretainto the absorbent body 4. The one side of the back sheet is the sidethat contacts with the clothing (underwear) of the wearer. The backsheet 3 is preferably moisture-permeable in addition to beingliquid-impermeable, in order to reduce mustiness during wear.

Examples for the back sheet 3 include waterproof treated nonwovenfabrics, films of synthetic resins (such as polyethylene, polypropyleneand polyethylene terephthalate), composite sheets comprising nonwovenfabrics and synthetic resin films (such as composite films having an airpermeable synthetic resin film bonded to a spunbond or spunlace nonwovenfabric), and SMS nonwoven fabrics comprising a highly water-resistantmeltblown nonwoven fabric sandwiched between high-strength spunbondnonwoven fabrics.

The absorbent body 4 contains an absorbent material that absorbs liquidexcreta, such as menstrual blood. The absorbent material contained inthe absorbent body 4 is not particularly restricted so long as it canabsorb and hold liquid excreta, such as menstrual blood. The absorbentmaterial may be, for example, water-absorbent fibers or ahigh-water-absorbing material (for example, a high-water-absorbent resinor high-water-absorbent fibers). The absorbent body 4 may also containadditives, such as antioxidants, light stabilizers, ultravioletabsorbers, neutralizers, nucleating agents, epoxy stabilizers,lubricants, antimicrobial agents, flame retardants, antistatic agents,pigments or plasticizers, as necessary.

Examples of water-absorbent fibers include wood pulp obtained using aconifer or broadleaf tree material as the starting material (forexample, mechanical pulp, such as groundwood pulp, refiner ground pulp,thermomechanical pulp and chemithermomechanical pulp; chemical pulp,such as Kraft pulp, sulfide pulp and alkaline pulp; and semichemicalpulp); mercerized pulp or crosslinked pulp obtained by chemicaltreatment of wood pulp; nonwood pulp, such as bagasse, kenaf, bamboo,hemp and cotton (for example, cotton linter); regenerated cellulose,such as rayon and fibril rayon; and semi-synthetic celluloses, such asacetates and triacetates, among which ground pulp is preferred from theviewpoint of low cost and easy shaping.

Examples of high-water-absorbing materials include starch-based,cellulose-based and synthetic polymer high-water-absorbing materials.Examples of starch-based or cellulose-based high-water-absorbingmaterials include starch-acrylic acid (acrylate) graft copolymer,saponified starch-acrylonitrile copolymer and crosslinked sodiumcarboxymethyl cellulose, and examples of synthetic polymer-basedhigh-water-absorbing materials include polyacrylic acid salt-based,polysulfonic acid salt-based, maleic anhydride salt-based,polyacrylamide-based, polyvinyl alcohol-based, polyethylene oxide-based,polyaspartic acid salt-based, polyglutamic acid salt-based, polyalginicacid salt-based, starch-based and cellulose-based high water-absorbentresins (Superabsorbent Polymers: SAP), among which polyacrylic acidsalt-based (especially sodium polyacrylate-based) high water-absorbentresins are preferred. Examples of high-water-absorbing material formsinclude particulate, filamentous and scaly forms, and in the case ofparticulates, the particle size is preferably 50 to 1000 μm and morepreferably 100 to 600 μm.

When the absorbent body 4 contains a high-water-absorbing material (forexample, a high-water-absorbing resin or high water-absorbent fibers),the content of the high-water-absorbing material will usually be 5 to 80mass %, preferably 10 to 60 mass % and more preferably 20 to 40 mass %of the absorbent body 4.

The absorbent body 4 may also contain silver, copper, zinc, silica,active carbon, aluminosilicate compounds, zeolite, or the like. Thesecan impart functions, such as deodorant, antibacterial or heat-absorbingeffects to the absorbent body.

The thickness and basis weight of the absorbent body 4 can beappropriately adjusted according to the properties desired for thesanitary napkin 1 (for example, absorption property, strength andlightweight property). The thickness of the absorbent body 4 willusually be 0.1 to 15 mm, preferably 1 to 10 mm and more preferably 2 to5 mm, and the basis weight will usually be 20 to 1000 g/m², preferably50 to 800 g/m² and more preferably 100 to 500 g/m². The thickness andbasis weight of the absorbent body 4 may be constant across the entireabsorbent body 4, or it may partially differ.

The absorbent body 4 may have a core containing an absorbent material,and a core wrap covering the core. The core wrap is not particularlyrestricted so long as it has liquid permeability and absorbent bodyretentivity. Examples for the core wrap include nonwoven fabrics, wovenfabrics, liquid permeation hole-formed synthetic resin films and meshednet-like sheets, among which tissues formed by a wet method using groundpulp as the main material are preferred from the viewpoint of low cost.

In addition to the top sheet 2, the sanitary napkin 1 may be providedwith a second sheet positioned between the top sheet 2 and the absorbentbody 4, as a liquid-permeable layer. In this case, a blood slippingagent may be coated onto the second sheet.

The second sheet is not particularly restricted so long as it allowspassage of liquid excreta, such as menstrual blood, and the second sheetthickness, basis weight, density and other properties may beappropriately adjusted within ranges that allow passage of liquidexcreta, such as menstrual blood.

Examples for the second sheet include nonwoven fabrics, woven fabrics,liquid permeation hole-formed synthetic resin films and meshed net-likesheets. Examples of nonwoven fabrics include air-through nonwovenfabrics, spunbond nonwoven fabrics, point bond nonwoven fabrics,spunlace nonwoven fabrics, needle punching nonwoven fabrics, meltblownnonwoven fabrics, and their combinations (such as SMS), and examples offibers to compose the nonwoven fabrics include natural fibers (wool,cotton and the like), regenerated fibers (rayon, acetate and the like),inorganic fibers (glass fiber, carbon fibers and the like), syntheticresin fibers (polyolefins, such as polyethylene, polypropylene,polybutylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylatecopolymer, ethylene-acrylic acid copolymer and ionomer resins;polyesters, such as polyethylene terephthalate, polybutyleneterephthalate, polytrimethylene terephthalate and polylactic acid; andpolyamides, such as nylon). The nonwoven fabric may be combined withcomposite fibers, such as core/sheath fibers, side-by-side fibers andsea/island fibers, hollow type fibers; irregularly shaped fibers, suchas flat fibers, Y-shaped fibers or C-shaped fibers; solid crimpedfibers, such as latent crimped or developed crimped fibers, or splitfibers that have been split by a physical load, such as a water stream,heat, embossing or the like.

<Method for Producing Absorbent Article>

An embodiment of a method for producing an absorbent article accordingto the invention will now be described, using a method for producing asanitary napkin 1 as an example.

The production method according to this embodiment comprises a step offorming an absorbent body (step 1), a step of layering a top sheet onthe absorbent body (step 2), a step of layering a back sheet (step 3), astep of cutting out a sanitary napkin (step 4) and a step of coating thesanitary napkin with a blood slipping agent (step 5), and the productionapparatus 100 shown in FIG. 5 is used.

[Step 1]

Recesses 124 are formed at a prescribed pitch in the circumferentialdirection on the peripheral surface of a suction drum 120 rotating inthe machine direction MD, as a molding form in which the absorbent bodymaterial 122 is to be packed. When the suction drum 120 is rotated andthe recesses 124 approach the material feeder 121, the suction section126 acts on the recesses 124 and the absorbent body material 122supplied from the material feeder 121 is vacuum suctioned into therecesses 124. The material feeder 121 is formed to cover the suctiondrum 120, and the material feeder 121 supplies the absorbent bodymaterial 122 into the recesses 124 by air transport, forming anabsorbent body 4 in the recesses 124. The absorbent body 4 formed in therecesses 124 is transferred onto a carrier sheet 110 advancing in themachine direction MD.

[Step 2]

The top sheet 2 is layered on the absorbent body 4, forming a layeredbody 262.

Next, compressed grooves are formed if necessary in the layered body262. Compressed grooves are formed using an embossing apparatus 130. Theembossing apparatus 130 has an upper roll 131 provided with projections(not shown) on the outer peripheral surface, and a lower roll 132 havinga smooth outer peripheral surface. The projections of the upper roll 131are formed to correspond to the shapes and arrangement pattern of thecompressed grooves. When the layered body 262 passes between the upperroll 131 and lower roll 132 of the embossing apparatus 130, the layeredbody 262 becomes compressed in the thickness direction, and compressedgrooves are formed in the layered body 262. The compressed grooves areformed on the top sheet 2 around the excretory opening contact region 20or in the surrounding region of the excretory opening contact region 20.Formation of compressed grooves integrate the top sheet 2 with theabsorbent body 4. When the step of forming the compressed grooves withthe embossing apparatus 130 is unnecessary, it may be omitted.

[Step 3]

The back sheet 3 supplied from the back sheet roll 140 is layered on thesurface of the lower side of the layered body 134 (the side opposite thetop sheet) via an adhesive layer, to form a continuous section 144 ofthe sanitary napkin. When the step of forming compressed grooves with anembossing apparatus 130 is omitted, the layered body 134 and the layeredbody 262 are identical.

[Step 4]

A cutter 150 is used to cut the continuous section 144 of the sanitarynapkin, thereby cutting out a sanitary napkin.

[Step 5]

A blood slipping agent 161 is coated onto the top sheet 2 of thesanitary napkin using spray 160, thereby forming a blood slipping agentlayer on the surface of the top sheet 2. The blood slipping agent layeris formed in at least the excretory opening contact region 20 on theskin contact surface of the top sheet 2.

For this embodiment, the blood slipping agent was coated after cuttingout the sanitary napkin, but it may instead be coated at any stagebefore cutting, or it may be coated during the production steps for thetop sheet. In order to prevent dripping down of the blood slipping agentthat has been coated during production, the blood slipping agent ispreferably coated at a downstream stage of the production process, suchas immediately before packaging of the sanitary napkin.

The method for producing the sanitary napkin 1 may comprise, in additionto steps 1 to 5, also a step of forming seal sections 7 a, 7 b, 8 a, 8 band a step of forming pressure-sensitive adhesive sections 9 a, 9 b, 9c.

<Blood Slipping Agent>

The blood slipping agent has a kinematic viscosity of about 0.01 toabout 80 mm²/s at 40° C., a water holding percentage of about 0.05 toabout 4.0 mass %, and a weight-average molecular weight of less thanabout 1,000.

The 40° C. kinematic viscosity of the blood slipping agent may beappropriately adjusted in the range of about 0 to about 80 mm²/s, but itis preferably about 1 to about 70 mm²/s, more preferably about 3 toabout 60 mm²/s, even more preferably about 5 to about 50 mm²/s and yetmore preferably about 7 to about 45 mm²/s. As used herein, the “40° C.kinematic viscosity” may be referred to simply as “kinematic viscosity”.

The kinematic viscosity tends to be higher with a) a larger molecularweight of the blood slipping agent, b) a higher percentage of polargroups, such as carbonyl bonds (—CO—), ether bonds (—O—), carboxylgroups (—COOH) and hydroxyl groups (—OH), and c) a larger IOB.

In order to have a kinematic viscosity of about 0 to about 80 mm²/s at40° C., the melting point of the blood slipping agent is preferably nohigher than 45° C. This is because the kinematic viscosity will tend tobe higher if the blood slipping agent contains crystals at 40° C.

The significance of the kinematic viscosity of the blood slipping agentwill be explained below, but a kinematic viscosity exceeding about 80mm²/s will tend to result in high viscosity of the blood slipping agent,such that it will not as easily slip down from the projections to therecesses together with menstrual blood that has reached the skin contactsurface of the top sheet, and subsequently migrate into the absorbentbody.

The kinematic viscosity can be measured according to JIS K 2283:2000,“5. Kinematic Viscosity Test Method”, using a Cannon-Fenske reverse-flowviscometer, at a testing temperature of 40° C.

The water holding percentage of the blood slipping agent may beappropriately adjusted in the range of about 0.01 to about 4.0 mass %,but it is preferably about 0.02 to about 3.5 mass %, more preferablyabout 0.03 to about 3.0 mass %, even more preferably about 0.04 to about2.5 mass % and yet more preferably about 0.05 to about 2.0 mass %.

As used herein, “water holding percentage” means the percentage (mass)of water that can be held by a substance, and it may be measured in thefollowing manner.

(1) A 20 mL test tube, a rubber stopper, the substance to be measuredand deionized water are allowed to stand for a day and a night in athermostatic chamber at 40° C.

(2) Into the test tube in the thermostatic chamber there are charged 5.0g of the substance to be measured and 5.0 g of deionized water.

(3) The mouth of the test tube is closed with the rubber stopper in thethermostatic chamber, and the test tube is rotated once and allowed tostand for 5 minutes.

(4) A 3.0 g portion of the layer of the substance to be measured(usually the upper layer) is sampled into a glass dish with a diameterof 90 mm and a mass of W₀ (g), in the thermostatic chamber.

(5) The dish is heated at 105° C. for 3 hours in an oven to evaporateoff the moisture, and the mass W₁ (g) of each dish is measured.

(6) The water holding percentage is calculated by the following formula.

Water holding percentage (mass %)=100×[W ₀(g)−W ₁(g)]/3.0(g)

The measurement is conducted three times, and the average value isrecorded.

The significance of the water holding percentage of the blood slippingagent will be explained below, but a low water holding percentage willtend to lower the affinity between the blood slipping agent andmenstrual blood, thus impeding its migration into the absorbent bodytogether with menstrual blood that has reached the skin contact surfaceof the top sheet. If the water holding percentage is high, on the otherhand, the affinity between menstrual blood and the blood modifying agentwill become very high, similar to a surfactant, and absorbed menstrualblood will tend to remain on the skin contact surface of the top sheet,resulting in more red coloration of the skin contact surface of the topsheet.

The water holding percentage tends to be a larger value with a) asmaller molecular weight of the blood slipping agent, and b) a higherpercentage of polar groups, such as carbonyl bonds (—CO—), ether bonds(—O—), carboxyl groups (—COOH) and hydroxyl groups (—OH). This isbecause the blood slipping agent has greater hydrophilicity. The waterholding percentage will tend to have a larger value with a greater IOB,i.e with a higher inorganic value or with a lower organic value. This isalso because the blood slipping agent has greater hydrophilicity.

The significance of the kinematic viscosity and water holding percentageof the blood slipping agent will now be explained.

Menstrual blood excreted by the wearer and reaching the excretoryopening contact region contacts the blood slipping agent in theprojections and slips down together with it into the recesses, passingthrough the top sheet and migrating into the absorbent body.

More specifically, since the blood slipping agent with a kinematicviscosity of about 0.01 to about 80 mm²/s at 40° C. has very lowviscosity near the body temperature of the wearer and has a constantaffinity with the menstrual blood, it slips down from the projections tothe recesses together with the menstrual blood, and utilizing the energyduring sliding, the menstrual blood is able to pass through the recessesof the top sheet to rapidly migrate into the absorbent body. Also, sincethe blood slipping agent present in the projections has a water holdingpercentage of about 0.01 to about 4.0 mass %, presumably it has noaffinity with the hydrophilic components (blood plasma, etc.) in themenstrual blood, and therefore the menstrual blood does not easilyremain on the top sheet.

When the menstrual blood discharged by the wearer is a large amount ofmenstrual blood, the menstrual blood easily migrates into the absorbentbody, even when the kinetic energy of the menstrual blood itself is highand the kinematic viscosity of the blood slipping agent is relativelyhigh so that it does not easily slip down together with the menstrualblood, or when the water holding percentage value is relatively high sothat affinity with the hydrophilic components of the menstrual blood ishigh, or when the weight-average molecular weight value is relativelyhigh so that it does not easily slip down together with the menstrualblood, or when the skin contact surface of the top sheet does not havean irregular structure.

When the menstrual blood discharge by the wearer is a small amount ofmenstrual blood, on the other hand, the kinetic energy of the menstrualblood is low, and menstrual blood that has reached the skin contactsurface of the top sheet tends to easily pool in such cases.Consequently, the blood slipping agent slides down from the projectionsinto the recesses together with the menstrual blood, and the menstrualblood is drawn into the top sheet and then drawn into the absorbentbody, so that the menstrual blood can rapidly migrate into the absorbentbody.

The blood slipping agent has a weight-average molecular weight of lessthan about 1,000, and preferably a weight-average molecular weight ofless than about 900. This is because if the weight-average molecularweight is about 1,000 or higher, tack may be produced in the bloodslipping agent itself, tending to create a feeling of discomfort for thewearer. If the weight-average molecular weight increases, the viscosityof the blood slipping agent will tend to increase, and it will thereforebe difficult to lower the viscosity of the blood slipping agent byheating to a viscosity suitable for coating, and as a result, the bloodslipping agent may need to be diluted with a solvent.

The blood slipping agent preferably has a weight-average molecularweight of about 100 or greater, and more preferably it has aweight-average molecular weight of about 200 or greater. This is becauseif the weight-average molecular weight is low, the vapor pressure of theblood slipping agent may be increased, gasification may occur duringstorage and the amount may be reduced, often leading to problems, suchas odor during wear.

As used herein, “weight-average molecular weight” includes the conceptof a polydisperse compound (for example, a compound produced by stepwisepolymerization, an ester formed from a plurality of fatty acids and aplurality of aliphatic monohydric alcohols), and a simple compound (forexample, an ester formed from one fatty acid and one aliphaticmonohydric alcohol), and in a system comprising N_(i) molecules withmolecular weight M_(i) (i=1, or i=1, 2 . . . ), it refers to M_(w)determined by the following formula.

M _(w) =ΣN _(i) M _(i) ² /ΣN _(i) M _(i)

The weight-average molecular weights used throughout the presentspecification are the values measured by gel permeation chromatography(GPC), based on polystyrene.

The GPC measuring conditions may be the following, for example.

Device: Lachrom Elite high-speed liquid chromatogram by HitachiHigh-Technologies Corp.

Columns: SHODEX KF-801, KF-803 and KF-804, by Showa Denko K.K. Eluent:THF

Flow rate: 1.0 mL/minDriving volume: 100 μLDetection: RI (differential refractometer)

The weight-average molecular weights listed in the examples of thepresent specification were measured under the conditions describedbelow.

The blood slipping agent may have an IOB of about 0.00 to about 0.60.

The IOB (Inorganic Organic Balance) is an indicator of thehydrophilic-lipophilic balance, and as used herein, it is the valuecalculated by the following formula by Oda et al.:

IOB=Inorganic value/organic value.

The inorganic value and the organic value are based on the organicparadigm described in “Organic compound predictions and organicparadigms” by Fujita A., Kagaku no Ryoiki (Journal of JapaneseChemistry), Vol. 11, No. 10 (1957) p.719-725.

The organic values and inorganic values of major groups, according toFujita, are summarized in Table 1 below.

TABLE 1 Group Inorganic value Organic value —COOH 150 0 —OH 100 0—O—CO—O— 80 0 —CO— 65 0 —COOR 60 0 —O— 20 0 Triple bond 3 0 Double bond2 0 CH₂ 0 20 iso branching 0 −10 tert branching 0 −20 Light metal (salt)≧500 0

For example, in the case of an ester of tetradecanoic acid which has 14carbon atoms and dodecyl alcohol which has 12 carbon atoms, the organicvalue is 520 (CH₂, 20×26) and the inorganic value is 60 (—COOR, 60×1),and therefore IOB=0.12.

The IOB of the blood slipping agent is preferably between about 0.00 and0.60, more preferably between about 0.00 and 0.50, even more preferablybetween about 0.00 and 0.40 and most preferably between about 0.00 and0.30. If the IOB is within this range, it will be easier to meet theaforementioned conditions for the water-holding capacity and kinematicviscosity.

The blood slipping agent preferably has a melting point of no higherthan 45° C., and more preferably it has a melting point of no higherthan 40° C. If the blood slipping agent has a melting point of no higherthan 45° C., the blood slipping agent will more easily exhibit akinematic viscosity in the aforementioned range.

As used herein, the term “melting point” refers to the peak toptemperature for the endothermic peak during conversion from solid toliquid, upon measurement with a differential scanning calorimetryanalyzer at a temperature-elevating rate of 10° C./min. The meltingpoint may be measured using a Model DSC-60 DSC measuring apparatus byShimadzu Corp., for example.

If the blood slipping agent has a melting point of no higher than about45° C., it may be either liquid or solid at room temperature (about 25°C.), or in other words, the melting point may be either about 25° C. orhigher or below about 25° C., and for example, it may have a meltingpoint of about −5° C. or about −20° C.

The blood slipping agent does not have a lower limit for its meltingpoint, but its vapor pressure is preferably low. The vapor pressure ofthe blood slipping agent is preferably between about 0 and about 200 Pa,more preferably between about 0 and about 100 Pa, more preferablybetween about 0 and about 10 Pa, even more preferably between about 0and about 1 Pa and yet more preferably between about 0.0 and about 0.1Pa, at 25° C. (1 atmosphere).

Considering that the absorbent article of the present disclosure is tobe used in contact with the human body, the vapor pressure is preferablybetween about 0 and about 700 Pa, more preferably between about 0 andabout 100 Pa, more preferably between about 0 and about 10 Pa, even morepreferably between about 0 and about 1 Pa and yet more preferablybetween about 0.0 and about 0.1 Pa, at 40° C. (1 atmosphere). If thevapor pressure of the blood slipping agent is high, gasification mayoccur during storage and the amount may be reduced, often creatingproblems, such as odor during wear.

The melting point of the blood slipping agent may be selected dependingon the weather or duration of wear. For example, in regions with a meanatmospheric temperature of no higher than about 10° C., using a bloodslipping agent with a melting point of no higher than about 10° C. mayhelp the blood slipping agent function after excretion of menstrualblood, even if it has been cooled by the ambient temperature.

Also, when the absorbent article is to be used for a prolonged period oftime, the melting point of the blood slipping agent is preferably at thehigh end of the range of no higher than about 45° C. This is so that theblood slipping agent will not be easily affected by sweat or frictionduring wearing, and will not easily become biased even during prolongedwearing.

In the technical field, the skin contact surfaces of top sheets arecoated with surfactants in order to alter the surface tension ofmenstrual blood and promote rapid absorption of menstrual blood.However, the top sheet coated with the surfactant has very high affinityfor the hydrophilic components (blood plasma, etc.) in menstrual blood,and acts to attract them, tending to cause menstrual blood instead toremain on the top sheet. The blood slipping agent, unlike conventionallyknown surfactants, has low affinity with menstrual blood and thereforedoes not cause residue of menstrual blood on the top sheet and allowsrapid migration into the absorbent body.

The blood slipping agent is preferably selected from the groupconsisting of the following items (i)-(iii), and any combinationthereof:

(i) a hydrocarbon;

(ii) a compound having (ii-1) a hydrocarbon moiety, and (ii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety; and

(iii) a compound having (iii-1) a hydrocarbon moiety, (iii-2) one ormore, same or different groups selected from the group consisting ofcarbonyl group (—CO—) and oxy group (—O—) inserted between a C—C singlebond of the hydrocarbon moiety, and (iii-3) one or more, same ordifferent groups selected from the group consisting of carboxyl group(—COOH) and hydroxyl group (—OH) substituting a hydrogen of thehydrocarbon moiety.

As used herein, “hydrocarbon” refers to a compound composed of carbonand hydrogen, and it may be a chain hydrocarbon, such as a paraffinichydrocarbon (containing no double bond or triple bond, also referred toas “alkane”), an olefin-based hydrocarbon (containing one double bond,also referred to as “alkene”), an acetylene-based hydrocarbon(containing one triple bond, also referred to as “alkyne”), or ahydrocarbon or cyclic hydrocarbon comprising two or more bonds selectedfrom the group consisting of double bonds or triple bonds, such asaromatic hydrocarbons and alicyclic hydrocarbons.

Preferred as such hydrocarbons are chain hydrocarbons and alicyclichydrocarbons, with chain hydrocarbons being more preferred, paraffinichydrocarbons, olefin-based hydrocarbons and hydrocarbons with two ormore double bonds (containing no triple bond) being more preferred, andparaffinic hydrocarbons being even more preferred.

Chain hydrocarbons include straight-chain hydrocarbons andbranched-chain hydrocarbons.

When two or more oxy groups (—O—) are inserted in the compounds of (ii)and (iii) above, the oxy groups (—O—) are not adjacent. Thus, compounds(ii) and (iii) do not include compounds with continuous oxy groups (i.e.peroxides).

In the compounds of (iii), compounds in which at least one hydrogen onthe hydrocarbon moiety is substituted with a hydroxyl group (—OH) arepreferred over compounds in which at least one hydrogen on thehydrocarbon moiety is substituted with a carboxyl group (—COOH). This isbecause the carboxyl groups bond with metals and the like in menstrualblood, increasing the water holding percentage of the blood slippingagent, which may sometimes exceed the prescribed range. The same is truefrom the viewpoint of the IOB as well. As shown in Table 1, the carboxylgroups bond with metals and the like in menstrual blood, drasticallyincreasing the inorganic value from 150 to 400 or greater, and thereforea blood slipping agent with carboxyl groups can increase the IOB valueto more than about 0.60 during use.

The blood slipping agent is more preferably selected from the groupconsisting of the following items (i′)-(iii′), and any combinationthereof:

(i′) a hydrocarbon;

(ii′) a compound having (ii′-1) a hydrocarbon moiety, and (ii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety; and

(iii′) a compound having (iii′-1) a hydrocarbon moiety, (iii′-2) one ormore, same or different bonds selected from the group consisting ofcarbonyl bond (—CO—), ester bond (—COO—), carbonate bond (—OCOO—), andether bond (—O—) inserted between a C—C single bond of the hydrocarbonmoiety, and (iii′-3) one or more, same or different groups selected fromthe group consisting of carboxyl group (—COOH) and hydroxyl group (—OH)substituting a hydrogen on the hydrocarbon moiety.

When 2 or more identical or different bonds are inserted in a compoundof (ii′) or (iii′), that is, when 2 or more identical or different bondsselected from among carbonyl bonds (—CO—), ester bonds (—COO—),carbonate bonds (—OCOO—) and ether bonds (—O—) are inserted, the bondsare not adjacent to each other, and at least one carbon atom liesbetween each of the bonds.

The blood slipping agent more preferably has no more than about 1.8carbonyl bonds (—CO—), no more than two ester bonds (—COO—), no morethan about 1.5 carbonate bonds (—OCOO—), no more than about 6 etherbonds (—O—), no more than about 0.8 carboxyl groups (—COOH) and/or nomore than about 1.2 hydroxyl groups (—OH), per 10 carbon atoms in thehydrocarbon moiety.

The blood slipping agent is even more preferably selected from the groupconsisting of the following items (A)-(F), and any combination thereof:

(A) an ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(B) an ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety and (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting a hydrogen on the chain hydrocarbon moiety;

(C) an ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety;

(D) a compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of an ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—) inserted between a C—Csingle bond of the chain hydrocarbon moiety;

(E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkyl etherthereof; and

(F) a chain hydrocarbon.

[(A) Ester of (A1) a Compound Having a Chain Hydrocarbon Moiety and 2-4Hydroxyl Groups Substituting Hydrogens on the Chain Hydrocarbon Moiety,and (A2) a Compound Having a Chain Hydrocarbon Moiety and 1 CarboxylGroup Substituting a Hydrogen on the Chain Hydrocarbon Moiety]

The (A) ester of (A1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety, and (A2) a compound having a chain hydrocarbon moiety and 1carboxyl group substituting a hydrogen on the chain hydrocarbon moiety(hereunder also referred to as “compound (A)”) does not need to have allof the hydroxyl groups esterified, so long as it has the aforementionedkinematic viscosity, water holding percentage and weight-averagemolecular weight.

Examples for the (A1) compound having a chain hydrocarbon moiety and 2-4hydroxyl groups substituting at hydrogens of the chain hydrocarbonmoiety (hereunder also referred to as “compound (A1)”) include chainhydrocarbon tetraols, such as alkanetetraols including pentaerythritol,chain hydrocarbon triols, such as alkanetriols including glycerin, andchain hydrocarbon diols, such as alkanediols including glycols.

Compounds for the (A2) compound having a chain hydrocarbon moiety andone carboxyl group substituting at a hydrogen of the chain hydrocarbonmoiety include compounds in which one hydrogen on the hydrocarbon issubstituted with one carboxyl group (—COOH), such as fatty acids.

Examples for compound (A) include (a₁) an ester of a chain hydrocarbontetraol and at least one fatty acid, (a₂) an ester of a chainhydrocarbon triol and at least one fatty acid, and (a₃) an ester of achain hydrocarbon diol and at least one fatty acids.

[(a₁) Ester of a Chain Hydrocarbon Tetraol and at Least One Fatty Acid]

Examples of esters of a chain hydrocarbon tetraol and at least one fattyacid include tetraesters of pentaerythritols and fatty acids,represented by the following formula (1):

triesters of pentaerythritol and fatty acids, represented by thefollowing formula (2):

diesters of pentaerythritol and fatty acids, represented by thefollowing formula (3):

and monoesters of pentaerythritol and fatty acids, represented by thefollowing formula (4).

(In the formulas, R¹ to R⁴ each represent a chain hydrocarbon.)

The fatty acids composing the esters of pentaerythritol and fatty acids(R¹COOH, R²COOH, R³COOH, and R⁴COOH) are not particularly restricted solong as the pentaerythritol and fatty acid esters satisfy the conditionsfor the kinematic viscosity, water holding percentage and weight-averagemolecular weight, and for example, there may be mentioned saturatedfatty acids, such as a C₂-C₃₀ saturated fatty acids, including aceticacid (C₂) (C₂ representing the number of carbons, corresponding to thenumber of carbons of R¹C, R²C, R³C or R⁴C, same hereunder), propanoicacid (C₃), butanoic acid (C₄) and its isomers, such as 2-methylpropanoicacid (C₄), pentanoic acid (C₅) and its isomers, such as 2-methylbutanoicacid (C₅) and 2,2-dimethylpropanoic acid (C₅), hexanoic acid (C₆),heptanoic acid (C₇), octanoic acid (C₈) and its isomers, such as2-ethylhexanoic acid (C₈), nonanoic acid (C₉), decanoic acid (C₁₀),dodecanoic acid (C₁₁), tetradecanoic acid (C₁₄), hexadecanoic acid(C₁₆), heptadecanoic acid (C₁₇), octadecanoic acid (C₁₈), eicosanoicacid (C₂₀), docosanoic acid (C₂₂), tetracosanoic acid (C₂₄),hexacosanoic acid (C₂₆), octacosanoic acid (C₂₈) and triacontanoic acid(C₃₀), as well as isomers of the foregoing that have not been mentioned.

The fatty acid may also be an unsaturated fatty acid. Examples ofunsaturated fatty acids include C₃-C₂₀ unsaturated fatty acids, such asmonounsaturated fatty acids including crotonic acid (C₄), myristoleicacid (C₁₄), palmitoleic acid (C₁₆), oleic acid (C₁₈), elaidic acid(C₁₈), vaccenic acid (C₁₈), gadoleic acid (C₂₀) and eicosenoic acid(C₂₀), di-unsaturated fatty acids including linolic acid (C₁₈) andeicosadienoic acid (C₂₀), tri-unsaturated fatty acids includinglinolenic acids, such as α-linolenic acid (C₁₈) and γ-linolenic acid(C₁₈), pinolenic acid (C₁₈), eleostearic acids, such as α-eleostearicacid (C₁₈) and β-eleostearic acid (C₂₀), Mead acid (C₂₀),dihomo-γ-linolenic acid (C₂₀) and eicosatrienoic acid (C₂₀),tetra-unsaturated fatty acids including stearidonic acid (C₂₀),arachidonic acid (C₂₀) and eicosatetraenoic acid (C₂₀),penta-unsaturated fatty acids including bosseopentaenoic acid (C₁₈) andeicosapentaenoic acid (C₂₀), as well as partial hydrogen adducts of theforegoing.

Considering the potential for degradation by oxidation and the like, theester of pentaerythritol and a fatty acid is preferably an ester ofpentaerythritol and a fatty acid derived from a saturated fatty acid, orin other words, an ester of pentaerythritol and a saturated fatty acid.

Also, in order to lower the water holding percentage value, the ester ofpentaerythritol and a fatty acid is preferably a diester, triester ortetraester, more preferably a triester or tetraester, and mostpreferably a tetraester.

From the viewpoint of the IOB being from about 0.00 to about 0.60, for atetraester of pentaerythritol and a fatty acid, the total number ofcarbons of the fatty acid composing the tetraester of thepentaerythritol and fatty acid, i.e. the total number of carbons of theR¹C, R²C, R³C and R⁴C portions in formula (1), is preferably about 15(the IOB is 0.60 when the total number of carbon atoms is 15).

Examples of tetraesters of pentaerythritol and fatty acids includetetraesters of pentaerythritol with hexanoic acid (C₆), heptanoic acid(C₇), octanoic acid (C₈), such as 2-ethylhexanoic acid (C₈), nonanoicacid (C₉), decanoic acid (C₁₀) and/or dodecanoic acid (C₁₂).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in atriester of pentaerythritol and a fatty acid, the total number ofcarbons of the fatty acid composing the triester of the pentaerythritoland fatty acid, i.e. the total number of carbons of the R¹C, R²C and R³Cportions in formula (2), is preferably about 19 or greater (the IOB is0.58 when the number of carbon atoms is 19).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiester of pentaerythritol and a fatty acid, the total number of carbonsof the fatty acid composing the diester of the pentaerythritol and fattyacid, i.e. the total number of carbons of the R¹C and R²C portion informula (3), is preferably about 22 or greater (the IOB is 0.59 when thenumber of carbon atoms is 22).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoester of pentaerythritol and a fatty acid, the total number ofcarbons of the fatty acid composing the monoester of the pentaerythritoland fatty acid, i.e. the number of carbons of the R¹C portion in formula(4), is preferably about 25 or greater (the IOB is 0.60 when the numberof carbon atoms is 25). The effects of double bonds, triple bonds,iso-branches and tert-branches are not considered in this calculation ofthe IOB (same hereunder).

Commercial products which are esters of pentaerythritol and fatty acidsinclude UNISTAR H-408BRS and H-2408BRS-22 (mixed product) (both productsof NOF Corp.).

[(a₂) Ester of a Chain Hydrocarbon Triol and at Least One Fatty Acid]

Examples of esters of a chain hydrocarbon triol and at least one fattyacid include triesters of glycerin and fatty acids, represented byformula (5):

diesters of glycerin and fatty acids, represented by the followingformula (6):

and monoesters of glycerin and fatty acids, represented by the followingformula (7):

wherein R⁵-R⁷ each represent a chain hydrocarbon.

The fatty acid composing the ester of glycerin and a fatty acid (R⁵COOH,R⁶COOH and R⁷COOH) is not particularly restricted so long as the esterof glycerin and a fatty acid satisfies the conditions for the kinematicviscosity, water holding percentage and weight-average molecular weight,and for example, there may be mentioned the fatty acids mentioned forthe “(a₁) Ester of chain hydrocarbon tetraol and at least one fattyacid”, namely saturated fatty acids and unsaturated fatty acids, and inconsideration of the potential for degradation by oxidation and thelike, the ester is preferably a glycerin and fatty acid ester derivedfrom a saturated fatty acid, or in other words, an ester of glycerin anda saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage value,the ester of glycerin and a fatty acid is preferably a diester ortriester, and more preferably a triester.

A triester of glycerin and a fatty acid is also known as a triglyceride,and examples include triesters of glycerin and octanoic acid (C₈),triesters of glycerin and decanoic acid (C₁₀), triesters of glycerin anddodecanoic acid (C₁₂), triesters of glycerin and 2 or more differentfatty acids, and mixtures of the foregoing.

Examples of triesters of glycerin and 2 or more fatty acids includetriesters of glycerin with octanoic acid (C₈) and decanoic acid (C₁₀),triesters of glycerin with octanoic acid (C₈), decanoic acid (C₁₀) anddodecanoic acid (C₁₂), and triesters of glycerin with octanoic acid(C₈), decanoic acid (C₁₀), dodecanoic acid (C₁₂), tetradecanoic acid(C₁₄), hexadecanoic acid (C₁₆) and octadecanoic acid (C₁₈).

Considered from the viewpoint of obtaining a melting point of no higherthan about 45° C., the triester of glycerin and a fatty acid preferablyhas a total number of carbon atoms in the fatty acid composing thetriester of glycerin and a fatty acid, i.e. a total number of carbons inthe R⁵C, R⁶C and R⁷C portions in formula (5), of about 40 or less.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in atriester of glycerin and a fatty acid, the total number of carbons ofthe fatty acid composing the triester of the glycerin and fatty acid,i.e. the total number of carbons of the R⁵C, R⁶C and R⁷C portions informula (5), is preferably about 12 or greater (the IOB is 0.60 when thetotal number of carbon atoms is 12).

Triesters of glycerin and fatty acids, being aliphatic and thereforepotential constituent components of the human body, are preferred fromthe viewpoint of safety.

Commercial products of triesters of glycerin and fatty acids includetri-coconut fatty acid glycerides, NA36, PANACET 800, PANACET 800B andPANACET 810S, and tri-C2L oil fatty acid glycerides and tri-CL oil fattyacid glycerides (all products of NOF Corp.).

A diester of glycerin and a fatty acid is also known as a diglyceride,and examples include diesters of glycerin and decanoic acid (C₁₀),diesters of glycerin and dodecanoic acid (C₁₂), diesters of glycerin andhexadecanoic acid (C₁₆), diesters of glycerin and 2 or more differentfatty acids, and mixtures of the foregoing.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiester of glycerin and a fatty acid, the total number of carbons of thefatty acid composing the diester of the glycerin and fatty acid, i.e.the total number of carbons of the R⁵C and R⁶C portions in formula (6),is preferably about 16 or greater (the IOB is 0.58 when the total numberof carbon atoms is 16).

Monoesters of glycerin and fatty acids are also known as monoglycerides,and examples include glycerin and octadecanoic acid (C₁₈) monoester, andglycerin and docosanoic acid (C₂₂) monoester.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoester of glycerin and a fatty acid, the total number of carbons ofthe fatty acid composing the monoester of the glycerin and fatty acid,i.e. the number of carbons of the R⁵C portion in formula (7), ispreferably about 19 or greater (the IOB is 0.59 when the number ofcarbon atoms is 19).

[(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty Acid]

Examples of esters of a chain hydrocarbon diol and at least one fattyacid include monoesters and diesters of fatty acids with C₂-C₆ chainhydrocarbon diols, such as C₂-C₆ glycols, including ethylene glycol,propylene glycol, butylene glycol, pentylene glycol and hexylene glycol.

Specifically, examples of esters of a chain hydrocarbon diol and atleast one fatty acid include diesters of C₂-C₆ glycols and fatty acids,represented by the following formula (8):

R⁸COOC_(k)H_(2k)OCOR⁹  (8)

wherein k represents an integer of 2 to 6, and R⁸ and R⁹ each representa chain hydrocarbon,

and monoesters of C₂-C₆ glycols and fatty acids, represented by thefollowing formula (9):

R⁸COOC_(k)H_(2k)OH  (9)

wherein k represents an integer of 2 to 6, and R⁸ is a chainhydrocarbon.

The fatty acid to be esterified in an ester of a C₂-C₆ glycol and afatty acid (corresponding to R⁸COOH and R⁹COOH in formula (8) andformula (9)) is not particularly restricted so long as the ester of theC₂-C₆ glycol and fatty acid satisfies the conditions for the kinematicviscosity, water holding percentage and weight-average molecular weight,and for example, there may be mentioned the fatty acids mentioned abovefor the “(a₁) Ester of chain hydrocarbon tetraol and at least one fattyacid”, namely saturated fatty acids and unsaturated fatty acids, and inconsideration of the potential for degradation by oxidation and thelike, it is preferably a saturated fatty acid.

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiester of butylene glycol represented by formula (8) (k=4) and a fattyacid, the total number of carbons of the R⁸C and R⁹C portions ispreferably about 6 or greater (the IOB is 0.60 when the total number ofcarbon atoms is 6).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoester of ethylene glycol represented by formula (9) (k=2) and afatty acid, the number of carbons of the R⁸C portion is preferably about12 or greater (the IOB is 0.57 when the number of carbon atoms is 12).

Considering the potential for degradation by oxidation and the like, theester of the C₂-C₆ glycol and fatty acid is preferably a C₂-C₆ glycoland fatty acid ester derived from a saturated fatty acid, or in otherwords, an ester of a C₂-C₆ glycol and a saturated fatty acid.

Also, from the viewpoint of lowering the water holding percentage value,the ester of the C₂-C₆ glycol and fatty acid is preferably a glycol andfatty acid ester derived from a glycol with a greater number of carbons,such as an ester of a glycol and a fatty acid derived from butyleneglycol, pentylene glycol or hexylene glycol.

Also, from the viewpoint of lowering the water holding percentage value,the ester of a C₂-C₆ glycol and fatty acid is preferably a diester.

Examples of commercial products of esters of C₂-C₆ glycols and fattyacids include COMPOL BL and COMPOL BS (both products of NOF Corp.).

[(B) Ether of (B1) a Compound Having a Chain Hydrocarbon Moiety and 2-4Hydroxyl Groups Substituting Hydrogens on the Chain Hydrocarbon Moietyand (B2) a Compound Having a Chain Hydrocarbon Moiety and 1 HydroxylGroup Substituting a Hydrogen on the Chain Hydrocarbon Moiety]

The (B) ether of (B1) a compound having a chain hydrocarbon moiety and2-4 hydroxyl groups substituting hydrogens on the chain hydrocarbonmoiety and (B2) a compound having a chain hydrocarbon moiety and 1hydroxyl group substituting a hydrogen on the chain hydrocarbon moiety(hereunder also referred to as “compound (B)”) does not need to have allof the hydroxyl groups etherified, so long as it has the aforementionedkinematic viscosity, water holding percentage and weight-averagemolecular weight.

The (B1) compound having a chain hydrocarbon moiety and 2-4 hydroxylgroups substituting at hydrogens of the chain hydrocarbon moiety(hereunder also referred to as “compound (B1)”), may be pentaerythritol,glycerin or glycol, for example, mentioned as compound (A1) for“compound (A)”.

The (B2) compound having a chain hydrocarbon moiety and one hydroxylgroup substituting at a hydrogen of the chain hydrocarbon moiety(hereunder also referred to as “compound (B2)”) may be, for example, acompound in which one hydrogen of the hydrocarbon is substituted withone hydroxyl group (—OH), such as an aliphatic monohydric alcohol, whichmay be a saturated aliphatic monohydric alcohol or an unsaturatedaliphatic monohydric alcohol.

Examples of saturated aliphatic monohydric alcohols include C₁-C₂₀saturated aliphatic monohydric alcohols, such as methyl alcohol (CO (C₁representing the number of carbon atoms, same hereunder), ethyl alcohol(CO, propyl alcohol (CO and its isomers, including isopropyl alcohol(C₃), butyl alcohol (CO and its isomers, including sec-butyl alcohol (COand tert-butyl alcohol (C₄), pentyl alcohol (C₅), hexyl alcohol (C₆),heptyl alcohol (C₇), octyl alcohol (CO and its isomers, including2-ethylhexyl alcohol (C₈), nonyl alcohol (C₉), decyl alcohol (C₁₀),dodecyl alcohol (C₁₂), tetradecyl alcohol (C₁₄), hexadecyl alcohol(C₁₆), heptadecyl alcohol (C₁₇), octadecyl alcohol (C₁₈) and eicosylalcohol (C₂₀), as well as their isomers other than those mentioned.

Unsaturated aliphatic monohydric alcohols include those wherein one C—Csingle bond of a saturated aliphatic monohydric alcohol mentioned aboveis replaced with a C═C double bond, such as oleyl alcohol, and forexample, such alcohols are commercially available by New Japan ChemicalCo., Ltd. as the RIKACOL Series and UNJECOL Series.

Examples for compound (B) include (b₁) ethers of a chain hydrocarbontetraol and at least one aliphatic monohydric alcohol, such asmonoethers, diethers, triethers and tetraethers, preferably diethers,triethers and tetraethers, more preferably triethers and tetraethers andeven more preferably tetraethers, (b₂) ethers of a chain hydrocarbontriol and at least one aliphatic monohydric alcohol, such as monoethers,diethers and triethers, preferably diethers and triethers and morepreferably triethers, and (b₃) ethers of a chain hydrocarbon diol and atleast one aliphatic monohydric alcohol, such as monoethers and diethers,and preferably diethers.

Examples of ethers of a chain hydrocarbon tetraol and at least onealiphatic monohydric alcohol include tetraethers, triethers, diethersand monoethers of pentaerythritol and aliphatic monohydric alcohols,represented by the following formulas (10) to (13):

wherein R¹⁰-R¹³ each represent a chain hydrocarbon.

Examples of ethers of a chain hydrocarbon triol and at least onealiphatic monohydric alcohol include triethers, diethers and monoethersof glycerin and aliphatic monohydric alcohols, represented by thefollowing formulas (14) to (16):

wherein R¹⁴-R¹⁶ each represent a chain hydrocarbon.

Ethers of a chain hydrocarbon diol and at least one aliphatic monohydricalcohol include diethers of C₂-C₆ glycols and aliphatic monohydricalcohols, represented by the following formula (17):

R¹⁷OC_(n)H_(2n)OR¹⁸  (17)

wherein n is an integer of 2 to 6, and R¹⁷ and R¹⁸ are each a chainhydrocarbon,

and monoethers of C₂-C₆ glycols and aliphatic monohydric alcohols,represented by the following formula (18):

R¹⁷OC_(n)H_(2n)OH  (18)

wherein n is an integer of 2 to 6, and R¹⁷ is a chain hydrocarbon.

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a tetraether of pentaerythritol and an aliphatic monohydric alcohol,the total number of carbon atoms of the aliphatic monohydric alcoholcomposing the tetraether of pentaerythritol and the aliphatic monohydricalcohol, i.e. the total number of carbon atoms of the R¹⁰, R¹¹, R¹² andR¹³ portions in formula (10), is preferably about 4 or greater (the IOBis 0.44 when the total number of carbon atoms is 4).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a triether of pentaerythritol and an aliphatic monohydric alcohol,the total number of carbon atoms of the aliphatic monohydric alcoholcomposing the triether of pentaerythritol and the aliphatic monohydricalcohol, i.e. the total number of carbon atoms of the R¹⁰, R¹¹ and R¹²portions in formula (11), is preferably about 9 or greater (the IOB is0.57 when the total number of carbon atoms is 9).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a diether of pentaerythritol and an aliphatic monohydric alcohol, thetotal number of carbon atoms of the aliphatic monohydric alcoholcomposing the diether of pentaerythritol and the aliphatic monohydricalcohol, i.e. the total number of carbon atoms of the R¹⁰ and R¹¹portions in formula (12), is preferably about 15 or greater (the IOB is0.60 when the total number of carbon atoms is 15).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a monoether of pentaerythritol and an aliphatic monohydric alcohol,the number of carbon atoms of the aliphatic monohydric alcohol composingthe monoether of pentaerythritol and the aliphatic monohydric alcohol,i.e. the number of carbon atoms of the R¹⁰ portion in formula (13), ispreferably about 22 or greater (the IOB is 0.59 when the number ofcarbon atoms is 22).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a triether of glycerin and an aliphatic monohydric alcohol, the totalnumber of carbon atoms of the aliphatic monohydric alcohol composing thetriether of glycerin and the aliphatic monohydric alcohol, i.e. thetotal number of carbon atoms of the R¹⁴, R¹⁵ and R¹⁶ portions in formula(14), is preferably about 3 or greater (the IOB is 0.50 when the totalnumber of carbon atoms is 3).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a diether of glycerin and an aliphatic monohydric alcohol, the totalnumber of carbon atoms of the aliphatic monohydric alcohol composing thediether of glycerin and the aliphatic monohydric alcohol, i.e. the totalnumber of carbon atoms of the R¹⁴ and R¹⁵ portions in formula (15), ispreferably about 9 or greater (the IOB is 0.58 when the total number ofcarbon atoms is 9).

From the viewpoint of the IOB being between about 0.00 and about 0.60,in a monoether of glycerin and an aliphatic monohydric alcohol, thenumber of carbon atoms of the aliphatic monohydric alcohol composing themonoether of glycerin and the aliphatic monohydric alcohol, i.e. thenumber of carbon atoms of the R¹⁴ portion in formula (16), is preferably16 or greater (the IOB is 0.58 when the number of carbon atoms is 16).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in adiether of butylene glycol represented by formula (17) (n=4) and analiphatic monohydric alcohol, the total number of carbon atoms of theR¹⁷ and R¹⁸ portions is preferably about 2 or greater (the IOB is 0.33when the total number of carbon atoms is 2).

From the viewpoint of the IOB being from about 0.00 to about 0.60, in amonoether of ethylene glycol represented by formula (18) (n=2) and analiphatic monohydric alcohol, the number of carbon atoms of the R¹⁷portion is preferably about 8 or greater (the IOB is 0.60 when thenumber of carbon atoms is 8).

Compound (B) can be produced by dehydrating condensation of compound(B1) and compound (B2) in the presence of an acid catalyst.

[(C) Ester of (C1) a Carboxylic Acid, Hydroxy Acid, Alkoxy Acid orOxoacid Comprising a Chain Hydrocarbon Moiety and 2-4 Carboxyl GroupsSubstituting Hydrogens on the Chain Hydrocarbon Moiety and (C2) aCompound Having a Chain Hydrocarbon Moiety and 1 Hydroxyl GroupSubstituting a Hydrogen on the Chain Hydrocarbon Moiety]

The (C) ester of (C1) a carboxylic acid, hydroxy acid, alkoxy acid oroxoacid comprising a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens on the chain hydrocarbon moiety and (C2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety (hereunder alsoreferred to as “compound (C)”) does not need to have all of the carboxylgroups esterified so long as it has the aforementioned kinematicviscosity, water holding percentage and weight-average molecular weight.

Examples for the (C1) carboxylic acid, hydroxy acid, alkoxy acid oroxoacid including a chain hydrocarbon moiety and 2-4 carboxyl groupssubstituting hydrogens of the chain hydrocarbon moiety (hereunder alsoreferred to as “compound (C1)”) include chain hydrocarbon carboxylicacids with 2-4 carboxyl groups, for example, chain hydrocarbondicarboxylic acids, which include alkanedicarboxylic acids, such asethanedioic acid, propanedioic acid, butanedioic acid, pentanedioicacid, hexanedioic acid, heptanedioic acid, octanedioic acid, nonanedioicacid and decanedioic acid, chain hydrocarbon tricarboxylic acids, whichinclude alkanetricarboxylic acids, such as propanetrioic acid,butanetrioic acid, pentanetrioic acid, hexanetrioic acid, heptanetrioicacid, octanetrioic acid, nonanetrioic acid and decanetrioic acid, andchain hydrocarbon tetracarboxylic acids, which includealkanetetracarboxylic acids, such as butanetetraoic acid,pentanetetraoic acid, hexanetetraoic acid, heptanetetraoic acid,octanetetraoic acid, nonanetetraoic acid and decanetetraoic acid.

Also, compound (C1) includes chain hydrocarbon hydroxy acids with 2-4carboxyl groups, for example, chain hydrocarbon alkoxy acids with 2-4carboxyl groups, such as malic acid, tartaric acid, citric acid andisocitric acid, and O-acetylcitric acid or chain hydrocarbon oxoacidswith 2-4 carboxyl groups.

The (C2) compound with a chain hydrocarbon moiety and one hydroxyl groupsubstituting at a hydrogen of the chain hydrocarbon moiety may be any ofthose mentioned for “compound (B)”, such as an aliphatic monohydricalcohol.

Compound (C) may be (c₁) an ester, for example a monoester, diester,triester or tetraester, preferably a diester, triester or tetraester,more preferably a triester or tetraester and even more preferably atetraester, of a chain hydrocarbon tetracarboxylic acid, hydroxy acid,alkoxy acid or oxoacid with 4 carboxyl groups, and at least onealiphatic monohydric alcohol, (c₂) an ester, for example, a monoester,diester or triester, preferably a diester or triester and morepreferably a triester, of a chain hydrocarbon tricarboxylic acid,hydroxy acid, alkoxy acid or oxoacid with 3 carboxyl groups, and atleast one aliphatic monohydric alcohol, or (c₃) an ester, for example, amonoester or diester, and preferably a diester, of a chain hydrocarbondicarboxylic acid, hydroxy acid, alkoxy acid or oxoacid with 2 carboxylgroups, and at least one aliphatic monohydric alcohol.

Examples for compound (C) include dioctyl adipate and tributylO-acetylcitrate, of which commercially available products exist.

[(D) Compound Having a Chain Hydrocarbon Moiety and One Bond Selectedfrom the Group Consisting of an Ether Bond (—O—), Carbonyl Bond (—CO—),Ester Bond (—COO—) and Carbonate Bond (—OCOO—) Inserted Between a C—CSingle Bond of the Chain Hydrocarbon Moiety]

The (D) compound having a chain hydrocarbon moiety and one bond selectedfrom the group consisting of an ether bond (—O—), carbonyl bond (—CO—),ester bond (—COO—) and carbonate bond (—OCOO—) inserted between a C—Csingle bond of the chain hydrocarbon moiety (hereunder also referred toas “compound (D)”) may be (d₁) an ether of an aliphatic monohydricalcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃)an ester of a fatty acid and an aliphatic monohydric alcohol, or (d₄) adialkyl carbonate.

[(d₁) Ether of an Aliphatic Monohydric Alcohol and an AliphaticMonohydric Alcohol]

Ethers of aliphatic monohydric alcohols and aliphatic monohydricalcohols include compounds having the following formula (19):

R¹⁹OR²⁰  (19)

wherein R¹⁹ and R²⁰ each represent a chain hydrocarbon.

The aliphatic monohydric alcohol composing the ether (corresponding toR¹⁹OH and R²⁰OH in formula (19)) is not particularly restricted so longas the ether satisfies the conditions for the kinematic viscosity, waterholding percentage and weight-average molecular weight, and for example,it may be one of the aliphatic monohydric alcohols mentioned for“compound (B)”.

[(d₂) Dialkyl Ketone]

The dialkyl ketone may be a compound of the following formula (20):

R²¹COR²²  (20)

wherein R²¹ and R²² are each an alkyl group.

The dialkyl ketone may be a commercially available product, or it may beobtained by a known method, such as by oxidation of a secondary alcoholwith chromic acid or the like.

[(d₃) Ester of a Fatty Acid and an Aliphatic Monohydric Alcohol]

Examples of esters of fatty acids and aliphatic monohydric alcoholsinclude compounds having the following formula (21):

R²³COOR²⁴  (21)

wherein R²³ and R²⁴ each represent a chain hydrocarbon.

Examples of fatty acids composing esters (corresponding to R²³COOH informula (21)) include the fatty acids mentioned for the “(a₁) esters ofchain hydrocarbon tetraols and fatty acids”, and specifically theseinclude saturated fatty acids and unsaturated fatty acids, withsaturated fatty acids being preferred in consideration of the potentialfor degradation by oxidation and the like. The aliphatic monohydricalcohol composing the ester (corresponding to R²⁴OH in formula (21)) maybe one of the aliphatic monohydric alcohols mentioned for “compound(B)”.

Examples of esters of such fatty acids and aliphatic monohydric alcoholsinclude esters of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂) andesters of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂), andexamples of commercial products of esters of such fatty acids andaliphatic monohydric alcohols include ELECTOL WE20 and ELECTOL WE40(both products of NOF Corp.).

[(d₄) Dialkyl Carbonate]

The dialkyl carbonate may be a compound of the following formula (22):

R²⁵OC(═O)OR²⁶  (22)

wherein R²⁵ and R²⁶ are each an alkyl group.

The dialkyl carbonate may be a commercially available product, or it maybe synthesized by reaction between phosgene and an alcohol, reactionbetween formate chloride ester and an alcohol or alcoholate, or reactionbetween silver carbonate and an alkyl iodide.

From the viewpoint of the water holding percentage and vapor pressure,the weight-average molecular weight is preferably about 100 or greaterand more preferably about 200 or greater, for (d₁) an ether of analiphatic monohydric alcohol and an aliphatic monohydric alcohol, (d₂) adialkyl ketone, (d₃) an ester of a fatty acid and an aliphaticmonohydric alcohol, and (d₄) a dialkyl carbonate.

If the total number of carbon atoms is about 8 in a (d₂) dialkyl ketone,the melting point will be approximately −50° C. and the vapor pressurewill be about 230 Pa at 20° C., in the case of 5-nonanone, for example.

[(E) Polyoxy C₃-C₆ Alkylene Glycol, or Alkyl Ester or Alkyl EtherThereof]

The (E) polyoxy C₃-C₆ alkylene glycol, or its alkyl ester or alkyl ether(hereunder also referred to as “compound (E)”) may be (e₁) a polyoxyC₃-C₆ alkylene glycol, (e₂) an ester of a polyoxy C₃-C₆ alkylene glycoland at least one fatty acid, or (e₃) an ether of a polyoxy C₃-C₆alkylene glycol and at least one aliphatic monohydric alcohol. Thesewill now be explained.

[(e₁) Polyoxy C₃-C₆ Alkylene Glycol]

The polyoxy C₃-C₆ alkylene glycol is i) a homopolymer having onebackbone selected from the group consisting of oxy C₃-C₆ alkylenebackbones, i.e. oxyethylene backbone, oxypropylene backbone, oxybutylenebackbone, oxypentylene backbone and oxyhexylene backbone, and havinghydroxy groups at both ends, ii) a block copolymer having a backbone oftwo or more selected from among the aforementioned group and havinghydroxy groups at both ends, or iii) a random copolymer having abackbone of two or more selected from among the aforementioned group andhaving hydroxy groups at both ends.

A polyoxy C₃-C₆ alkylene glycol is represented by the following formula(23):

HO—(C_(m)H_(2m)O)_(n)—H  (23)

wherein m is an integer of 3-6.

The present inventors have found that with polypropylene glycol(corresponding to a homopolymer of formula (23) where m=3), thecondition for the water holding percentage is not satisfied when theweight-average molecular weight is less than about 1,000. Therefore,polypropylene glycol homopolymer is not included in the scope of theblood slipping agent described above, and propylene glycol should beincluded in the (e₁) polyoxy C₃-C₆ alkylene glycol only as a copolymeror random polymer with another glycol.

Incidentally, investigation by the present inventors suggests that withpolyethylene glycol (corresponding to a homopolymer of formula (23)where m=2), the condition for the kinematic viscosity and water holdingpercentage cannot be satisfied when the weight-average molecular weightis less than about 1,000.

From the viewpoint of the IOB being about 0.00 to about 0.60, whenformula (23) is polybutylene glycol (a homopolymer where m=4), forexample, preferably n about 7 (when n=7, the IOB is 0.57).

Examples of commercial products of poly C₃-C₆ alkylene glycols includeUNIOL™ PB-500 and PB-700 (all products of NOF Corp.).

[(e₂) Ester of a Polyoxy C₃-C₆ Alkylene Glycol and at Least One FattyAcid]

The ester of a polyoxy C₃-C₆ alkylene glycol and at least one fatty acidmay be one wherein one or both of the OH ends of a polyoxy C₃-C₆alkylene glycol mentioned above under “(e₁) Polyoxy C₃-C₆ alkyleneglycol” are esterified by a fatty acid, i.e. a monoester or a diester.

Examples of fatty acids to be esterified in the ester of a polyoxy C₃-C₆alkylene glycol and at least one fatty acid include the fatty acidsmentioned above under “(a₁) Ester of chain hydrocarbon tetraol and atleast one fatty acid”, and specifically these include saturated fattyacids and unsaturated fatty acids, with saturated fatty acids beingpreferred in consideration of the potential for degradation by oxidationand the like.

[(e₃) Ether of a Polyoxy C₃-C₆ Alkylene Glycol and at Least OneAliphatic Monohydric Alcohol]

The ether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphaticmonohydric alcohol may be one wherein one or both of the OH ends of apolyoxy C₃-C₆ alkylene glycol mentioned above under “(e₁) Polyoxy C₃-C₆alkylene glycol” are etherified by an aliphatic monohydric alcohol, i.e.a monoether or diether.

In an ether of a polyoxy C₃-C₆ alkylene glycol and at least onealiphatic monohydric alcohol, the aliphatic monohydric alcohol to beetherified may be an aliphatic monohydric alcohol among those mentionedfor “compound (B)”.

[(F) Chain Hydrocarbon]

Examples of chain hydrocarbons include (f₁) chain alkanes, such asstraight-chain alkanes and branched chain alkanes. Straight-chainalkanes with melting points of no higher than about 45° C. have up toabout 22 carbon atoms, and at a vapor pressure of 1 atmosphere and about0.01 Pa or less at 25° C., the number of carbon atoms is 13 or greater.Branched chain alkanes tend to have lower melting points thanstraight-chain alkanes, given the same number of carbon atoms. Branchedchain alkanes may therefore include those with 22 and more carbon atoms,even with melting points of below about 45° C.

Examples of commercially available hydrocarbon products include PARLEAM6 (NOF Corp.).

At least the projections 8 of the excretory opening contact region 20may be coated with the blood slipping agent alone, or with a bloodslipping agent-containing composition comprising the blood slippingagent and at least one other component.

Such a blood slipping agent-containing composition will now bedescribed. Coating of the blood slipping agent-containing composition isthe same as coating of the blood slipping agent, and explanation thereofwill therefore be omitted.

[Blood Slipping Agent-Containing Composition]

The blood slipping agent-containing composition contains theaforementioned blood slipping agent and at least one other component.The other component is not particularly restricted so long as it doesnot inhibit the function and effect of the blood slipping agent, and itmay be any one commonly employed in absorbent articles of the field, andespecially top sheets.

Examples for the other component(s) include silicone oils, silicones,silicone-based resins and the like.

Examples for the other component(s) also include antioxidants, such asBHT (2,6-di-t-butyl-p-cresol), BHA (butylated hydroxyanisole) and propylgallate.

Further examples for the other component(s) include vitamins, such asnatural vitamins and synthetic vitamins. Examples of vitamins includewater-soluble vitamins, such as group B vitamins, including B₁, vitaminB₂, vitamin B₃, vitamin B₅, vitamin B₆, vitamin B₇, vitamin B₉ andvitamin B₁₂, and vitamin C.

Other examples of vitamins include fat-soluble vitamins, such as group Avitamins, group D vitamins, group E vitamins and group K vitamins. Thederivatives of these vitamins are also included.

Examples for the other component(s) include amino acids, such asalanine, arginine, lysine, histidine, proline and hydroxyproline, andpeptides.

Other examples for the other component(s) include zeolite, such asnatural zeolite, examples of which include analcite, chabazite,heulandite, natrolite, stilbite and thomosonite, and synthetic zeolite.

Still other examples for the other component(s) include cholesterol,hyaluronic acid, lecithin and ceramide.

Yet other examples for the other component(s) include drugs, such asskin astringents, anti-pimple medications, anti-wrinkle agents,anti-cellulite agents, skin whiteners, antimicrobial agents andantifungal agents.

Examples of skin astringents include zinc oxide, aluminum sulfate,tannic acid and the like, and oil-soluble skin astringents, such asfat-soluble polyphenols. Fat-soluble polyphenols include naturalfat-soluble polyphenols, such as barley extract, otogiriso extract,white deadnettle extract, chamomilla extract, burdock extract, salviaextract, linden extract, common lime extract, white birch extract,common horsetail extract, sage extract, salvia extract, walnut (J. regiaL. var. orientalis) extract, hibiscus extract, loquat leaf extract,Miquel's linden extract, hop extract, common horse-chestnut extract andcoix seed extract.

Examples of anti-pimple medications include salicylic acid, benzoylperoxide, resorcinol, sulfur, erythromycin and zinc.

Examples of anti-wrinkle agents include lactic acid, salicylic acid,salicylic acid derivatives, glycolic acid, phytic acid, lipoic acid andlysophosphatidic acid.

Examples of anti-cellulite agents include xanthine compounds, such asaminophylline, caffeine, theophylline and theobromine.

Examples of skin whiteners include niacinamide, kojic acid, arbutin,glucosamine and its derivatives, phytosterol derivatives, and ascorbicacid and its derivatives, as well as mulberry extract and placentaextract.

Examples for the other component(s) also include anti-inflammatorycomponents, pH regulators, antimicrobial agents, humectants, aromatics,pigments, dyes, pigments and plant extracts.

Examples of anti-inflammatory components include naturally-derivedanti-inflammatory drugs, such as peony, golden grass, otogiriso,chamomile, licorice, peach leaf, Japanese mugwort and perilla extract,and synthetic anti-inflammatory drugs, such as allantoin and dipotassiumglycyrrhizinate.

Examples of pH regulators include those that keep the skin weaklyacidic, such as malic acid, succinic acid, citric acid, tartaric acidand lactic acid.

Titanium oxide is an example of a pigment.

The blood slipping agent-containing composition contains the bloodslipping agent and the one or more other components at preferably about50 to about 99 mass % and about 1 to about 50 mass %, respectively, morepreferably about 60 to about 99 mass % and about 1 to about 40 mass %,respectively, even more preferably about 70 to about 99 mass % and about1 to about 30 mass %, respectively, yet more preferably about 80 toabout 99 mass % and about 1 to about 20 mass %, respectively, even yetmore preferably about 90 to 99 mass % and about 1 to about 10 mass %,respectively, and even yet more preferably about 95 to 99 mass % andabout 1 to about 5 mass %, respectively. This is from the viewpoint ofthe functions and effects of the blood slipping agent and the othercomponents.

The blood slipping agent-containing composition preferably contains asurfactant in not greater than the amount from hydrophilicizingtreatment of the top sheet or second sheet. More specifically, the bloodslipping agent-containing composition contains a surfactant in a basisweight range of preferably about 0.0 to about 1.0 g/m², more preferablyabout 0.0 to about 0.8 g/m², even more preferably about 0.1 to about 0.5g/m², and yet more preferably about 0.1 to about 0.3 g/m².

This is because when the amount of surfactant is increased, menstrualblood will tend to be retained in the top sheet. The surfactant,incidentally, has no water holding percentage. This is because there isno layer of the substance to be measured due to its mixture with water.

The blood slipping agent-containing composition contains water in abasis weight range of preferably about 0.0 to about 1.0 g/m², morepreferably about 0.0 to about 0.8 g/m², even more preferably about 0.1to about 0.5 g/m², and yet more preferably about 0.1 to about 0.3 g/m².Since water lowers the absorption performance of the absorbent article,the amount is preferably low.

Similar to the blood slipping agent, the blood slipping agent-containingcomposition, as a composition, has at 40° C., a kinematic viscosity ofpreferably about 0 to about 80 mm²/s, more preferably a kinematicviscosity of about 1 to about 70 mm²/s, even more preferably a kinematicviscosity of about 3 to about 60 mm²/s, yet more preferably a kinematicviscosity of about 5 to about 50 mm²/s, and even yet more preferably akinematic viscosity of about 7 to about 45 mm²/s.

If the kinematic viscosity of the blood slipping agent-containingcomposition exceeds 80 mm²/s, the viscosity will increase and the bloodslipping agent composition may not slide down into the interior of theabsorbent article as easily with menstrual blood that has reached theskin contact surface of the top sheet.

When the blood slipping agent-containing composition contains acomponent that is miscible with the blood slipping agent, as at leastone other component, the other component preferably has a weight-averagemolecular weight of less than about 1,000, and more preferably aweight-average molecular weight of less than about 900. This is becauseif the weight-average molecular weight is about 1,000 or higher, tackmay result in the blood slipping agent-containing composition itself,tending to create a feeling of discomfort for the wearer. If theweight-average molecular weight increases, the viscosity of the bloodslipping agent-containing composition will tend to increase, and it willtherefore be difficult to lower the viscosity of the blood slippingagent composition by heating to a viscosity suitable for coating, and asa result, the blood slipping agent may need to be diluted with asolvent.

The blood slipping agent-containing composition, as a composition, has awater holding percentage of about 0.01 to about 4.0 mass %, preferablyit has a water holding percentage of about 0.02 to about 3.5 mass %,more preferably it has a water holding percentage of about 0.03 to about3.0 mass %, even more preferably it has a water holding percentage ofabout 0.04 to about 2.5 mass %, and yet more preferably it has a waterholding percentage of about 0.05 to about 2.0 mass %.

A low water holding percentage value will tend to lower the affinitybetween the blood slipping agent composition and menstrual blood, thusinhibiting it from sliding down into the interior of the absorbentarticle with menstrual blood that has reached the skin contact surfaceof the top sheet.

When the blood slipping agent-containing composition contains solidmatter, it is preferably removed by filtration for measurement of thekinematic viscosity and water holding percentage.

EXAMPLES Test Example 1

The blood slipping agents used for the test examples are listed below.

[(a₁) Ester of a Chain Hydrocarbon Tetraol and at Least One Fatty Acid]

UNISTAR H-408BRS, product of NOF Corp.

-   -   Pentaerythritol tetra(2-ethylhexanoate), weight-average        molecular weight: approximately 640

UNISTAR H-2408BRS-22, product of NOF Corp.

-   -   Mixture of pentaerythritol tetra(2-ethylhexanoate) and        neopentylglycol di(2-ethylhexanoate) (58:42 as weight ratio),        weight-average molecular weight: approximately 520        [(a₂) Ester of a Chain Hydrocarbon Triol and at Least One Fatty        Acid]

Cetiol SB45DEO, Cognis Japan

-   -   Glycerin and fatty acid triester, with oleic acid or stearylic        acid as the fatty acid.

SOY42, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₁₄ fatty acid:C_(H) fatty        acid:C₁₈ fatty acid:C_(H) fatty acid (including both saturated        fatty acids and unsaturated fatty acids) at a mass ratio of        about 0.2:11:88:0.8, weight-average molecular weight: 880

Tri-C2L oil fatty acid glyceride, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C_(H) fatty        acid:C₁₂ fatty acid at a weight ratio of about 37:7:56,        weight-average molecular weight: approximately 570

Tri-CL oil fatty acid glyceride, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C₁₂ fatty        acid at a weight ratio of about 44:56, weight-average molecular        weight: approximately 570

PANACET 810s, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C_(H) fatty        acid at a weight ratio of about 85:15, weight-average molecular        weight: approximately 480

PANACET 800, product of NOF Corp.

-   -   Glycerin and fatty acid triester with octanoic acid (C8) as the        entire fatty acid portion, weight-average molecular weight:        approximately 470

PANACET 800B, product of NOF Corp.

-   -   Glycerin and fatty acid triester with 2-ethylhexanoic acid (C₈)        as the entire fatty acid portion, weight-average molecular        weight: approximately 470

NA36, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₁₆ fatty acid:C₁₈ fatty        acid:C_(H) fatty acid (including both saturated fatty acids and        unsaturated fatty acids) at a weight ratio of about 5:92:3,        weight-average molecular weight: approximately 880

Tri-coconut fatty acid glyceride, product of NOF Corp.

-   -   Glycerin and fatty acid triester with C₈ fatty acid:C₁₀ fatty        acid:C₁₂ fatty acid:C₁₄ fatty acid:C₁₆ fatty acid (including        both saturated fatty acids and unsaturated fatty acids) at a        weight ratio of about 4:8:60:25:3, weight-average molecular        weight: 670

Caprylic acid diglyceride, product of NOF Corp.

-   -   Glycerin and fatty acid diester with octanoic acid as the fatty        acid, weight-average molecular weight: approximately 340        [(a₃) Ester of a Chain Hydrocarbon Diol and at Least One Fatty        Acid]

UNISTAR H-208BRS, product of NOF Corp.

-   -   Neopentyl glycol di(2-ethylhexanoate), weight-average molecular        weight: approximately 360

COMPOL BL, product of NOF Corp.

-   -   Dodecanoic acid (C₁₂) monoester of butylene glycol,        weight-average molecular weight: approximately 270

COMPOL BS, product of NOF Corp.

-   -   Octadecanoic acid (C₁₈) monoester of butylene glycol,        weight-average molecular weight: approximately 350        [(c₂) Ester of a Chain Hydrocarbon Tricarboxylic Acid, Hydroxy        Acid, Alkoxy Acid or Oxoacid with 3 Carboxyl Groups, and at        Least One Aliphatic Monohydric Alcohol]

Tributyl O-acetylcitrate, product of Tokyo Kasei Kogyo Co., Ltd.

-   -   Weight-average molecular weight: approximately 400

Tributyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

-   -   Weight-average molecular weight: approximately 360        [(c₃) Ester of a Chain Hydrocarbon Dicarboxylic Acid, Hydroxy        Acid, Alkoxy Acid or Oxoacid with 2 Carboxyl Groups, and at        Least One Aliphatic Monohydric Alcohol]

Dioctyl adipate, product of Wako Pure Chemical Industries, Ltd.

-   -   Weight-average molecular weight: approximately 380        [(d₃) Esters of a Fatty Acid and Aliphatic Monohydric Alcohol]

ELECTOL WE20, product of NOF Corp.

-   -   Ester of dodecanoic acid (C₁₂) and dodecyl alcohol (C₁₂),        weight-average molecular weight: approximately 360

ELECTOL WE40, product of NOF Corp.

-   -   Ester of tetradecanoic acid (C₁₄) and dodecyl alcohol (C₁₂),        weight-average molecular weight: approximately 390        [(e₁) Polyoxy C₃-C₆ Alkylene Glycol]

UNIOL PB500, product of NOF Corp.

-   -   Polybutylene glycol, weight-average molecular weight:        approximately 500

UNIOL PB700, product of NOF Corp.

-   -   Polyoxybutylene polyoxypropylene glycol, weight-average        molecular weight: approximately 700        [(f₁) Chain Alkane]

PARLEAM 6, product of NOF Corp.

-   -   Branched chain hydrocarbon, produced by copolymerization of        liquid isoparaffin, isobutene and n-butene followed by hydrogen        addition, polymerization degree: approximately 5-10,        weight-average molecular weight: approximately 330

[Other Materials]

NA50, product of NOF Corp.

-   -   Glycerin and fatty acid triester obtained by addition of        hydrogen to NA36 for reduced proportion of double bonds from        unsaturated fatty acid starting material, weight-average        molecular weight: approximately 880

(Caprylic acid/capric acid) monoglyceride, product of NOF Corp.

-   -   Glycerin and fatty acid monoester, with octanoic acid (C₈) and        decanoic acid (C₁₀) at a weight ratio of about 85:15,        weight-average molecular weight: approximately 220

Monomuls 90-L2 lauric acid monoglyceride, product of Cognis Japan

Isopropyl citrate, product of Tokyo Kasei Kogyo Co., Ltd.

-   -   Weight-average molecular weight: approximately 230

Diisostearyl malate

-   -   Weight-average molecular weight: approximately 640

UNIOL PB1000R, product of NOF Corp.

-   -   Polybutylene glycol, weight-average molecular weight:        approximately 1,000

UNIOL D-250, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 250

UNIOL D-400, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 400

UNIOL D-700, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 700

UNIOL D-1000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 1,000

UNIOL D-1200, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 1,160

UNIOL D-2000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 2,030

UNIOL D-3000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 3,000

UNIOL D-4000, product of NOF Corp.

-   -   Polypropylene glycol, weight-average molecular weight:        approximately 4,000

PEG1500, product of NOF Corp.

-   -   Polyethylene glycol, weight-average molecular weight:        approximately 1,500-1,600

WILBRITE cp9, product of NOF Corp.

-   -   Polybutylene glycol compound with OH groups at both ends        esterified by hexadecanoic acid (C₁₆), weight-average molecular        weight: approximately 1,150

UNILUBE MS-70K, product of NOF Corp.

-   -   Stearyl ether of polypropylene glycol, approximately 15        repeating units, weight-average molecular weight: approximately        1,140

NONION S-6, product of NOF Corp.

-   -   Polyoxyethylene monostearate, approximately 7 repeating units,        weight-average molecular weight: approximately 880

UNILUBE 5TP-300 KB

-   -   Polyoxyethylenepolyoxypropylene pentaerythritol ether, produced        by addition of 5 mol of ethylene oxide and 65 mol of propylene        oxide to 1 mol of pentaerythritol, weight-average molecular        weight: 4,130

WILBRITE s753, product of NOF Corp.

-   -   Polyoxyethylene polyoxypropylene polyoxybutylene glycerin,        weight-average molecular weight: approximately 960

UNIOL TG-330, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 6        repeating units, weight-average molecular weight: approximately        330

UNIOL TG-1000, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 16        repeating units, weight-average molecular weight: approximately        1,000,

UNIOL TG-3000, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 16        repeating units, weight-average molecular weight: approximately        3,000

UNIOL TG-4000, product of NOF Corp.

-   -   Glyceryl ether of polypropylene glycol, approximately 16        repeating units, weight-average molecular weight: approximately        4,000

UNILUBE DGP-700, product of NOF Corp.

-   -   Diglyceryl ether of polypropylene glycol, approximately 9        repeating units, weight-average molecular weight: approximately        700

UNIOX HC60, product of NOF Corp.

-   -   Polyoxyethylene hydrogenated castor oil, weight-average        molecular weight: approximately 3,570

Vaseline, product of Cognis Japan

-   -   Petroleum-derived hydrocarbon, semi-solid

Test Example 2 Menstrual Blood Surface Residue Rate A, with Absorptionof Large Amount of Blood

A test was conducted to evaluate the absorption property of a sanitarynapkin after one-time absorption of a large amount of blood.

There were prepared a top sheet, formed of a hydrophilic agent-treatedair-through nonwoven fabric (composite fiber composed of polyester andpolyethylene terephthalate, basis weight: 35 g/m²), a second sheet,formed of an air-through nonwoven fabric (composite fiber composed ofpolyester and polyethylene terephthalate, basis weight: 30 g/m²), anabsorbent body comprising pulp (basis weight: 150 to 450 g/m², increasedat the center section), an acrylic super-absorbent polymer (basisweight: 15 g/m²) and tissue as a core wrap, a water-repellentagent-treated side sheet, and a back sheet composed of a polyethylenefilm.

The top sheet was a top sheet produced by the method described inJapanese Unexamined Patent Publication No. 2008-2034, having aridge-furrow structure, with a ridge thickness of approximately 1.5 mmand a furrow thickness of approximately 0.4 mm, and the pitch of theridge-furrow structure (ridge width+furrow width) was approximately 4 mmand open holes were formed in the furrows at an open area ofapproximately 15%.

UNISTAR H-408BRS (product of NOF Corp., tetraester of pentaerythritoland fatty acid) was selected as the blood slipping agent, and it wascoated onto the skin contact surface (ridge-furrow side) of the topsheet from a control seam HMA gun at room temperature, to a basis weightof 5.0 g/m². With an electron microscope it was confirmed that theH-408BRS was adhering onto the fiber surfaces as fine particulates.

A back sheet, an absorbent body, a second sheet, and a top sheet withthe ridge-furrow side facing upward, were stacked in that order to formsanitary napkin No. 1-1

Sanitary napkins No. 1-2 to No. 1-49 were produced, changing the bloodslipping agent from UNISTAR H-408BRS to the ones listed in Table 2. Eachblood slipping agent was used directly, when it was liquid at roomtemperature, or when the blood slipping agent was solid at roomtemperature it was heated to its melting point+20° C., and then acontrol seam HMA gun was used for atomization of the blood slippingagent and coating onto the skin contact surface of the top sheet to abasis weight of about 5 g/m².

The blood slipping agent was coated onto essentially the entire skincontact surface of the top sheet, and on both the ridges and furrows.

[Test Methods]

After measuring the mass W₂ (g) of the top sheet (the weight of the topsheet before the test), an acrylic board with an opened hole (200 mm×100mm, 125 g, with a 40 mm×10 mm hole opened at the center) was placed onthe top sheet, at the center section in the lengthwise direction andwidthwise direction of the absorbent article, and 4.0 g of horse EDTAblood at 37±1° C. (obtained by adding ethylenediaminetetraacetic acid(hereunder, “EDTA”) to horse blood to prevent coagulation) was droppedthrough the hole using a pipette.

After dropping the horse EDTA blood, the acrylic board was immediatelyremoved, the top sheet was taken off, the mass W₃ (g) (mass of the topsheet after the test) was measured and the “surface residue rate A (mass%)” was calculated by the following formula.

Surface residue rate A(mass %)=100×[W ₃(g)−W ₂(g)]/4.0(g)

The tack on the skin contact surface of the top sheet was measured at35° C., and evaluated on the following scale.

G: No tackF: Slight tack

P: Tack

The surface residue rate A and tack of each absorbent article, and theproperties of each blood slipping agent, are shown below in Table 2.FIG. 6 is an electron micrograph of the skin contact surface of a topsheet in a sanitary napkin wherein the top sheet comprises tri-C2L oilfatty acid glycerides.

TABLE 2 Water Weight- Surface Kinematic holding average Melting residueviscosity percentage molecular point rate A No. Blood slipping agent(mm²/s, 40° C.) (mass %) weight IOB (° C.) (mass %) Tack 1-1 H-408 BRS45 0.7 640 0.13 <−5 0.8 G 1-2 H-2408 BRS-22 22 0.8 520 0.18 <−5 0.8 G1-3 Tri-C2L oil fatty acid glyceride 20 <1.0 570 0.27 37 G 1-4 Tri-CLoil fatty acid glyceride 15 <1.0 570 0.28 38 G 1-5 PANACET 810s  9 0.3480 0.32 −5 0.8 G 1-6 PANACET 800 15 0.5 470 0.33 −5 1.8 G 1-7 PANACET800B 20 <1.0 470 0.33 −5 G 1-8 NA36 40 <1.0 880 0.16 37 G 1-9Tri-coconut oil fatty acid glyceride 25 <1.0 670 0.28 30 G 1-10 Caprylicacid diglyceride 25 2.7 340 0.58 <45 1.0 G 1-11 UNISTAR H-208BRS  8 0.7360 0.24 <−5 0.5 G 1-12 COMPOL BL 10 1.6 270 0.50 2 1.3 G 1-13 COMPOL BS35 0.3 350 0.36 37 2.5 G 1-14 Tributyl O-acetylcitrate 15 0.9 400 0.60<45 0.5 G 1-15 Tributyl citrate 12 0.6 360 0.78 <45 1.8 G 1-16 Dioctyladipate  7 0.4 380 0.27 <45 1.5 G 1-17 ELECTOL WE20 10 0.3 360 0.13 290.5 G 1-18 ELECTOL WE40 15 0.5 390 0.12 37 2.3 G 1-19 UNIOL PB500 40 3.6500 0.44 <45 2.5 G 1-20 UNIOL PB700 50 2.3 700 0.49 −5 1.3 G 1-21PARLEAM 6  5 0.06 330 0.00 −5 2.0 G 1-22 NA50  80<< —* 880 0.18 52 4.3 G1-23 (Caprylic acid/capric acid) monoglyceride 70 4.0<< 220 1.15 <45 5.0G 1-24 90-L2 lauric acid monoglyceride  80<< 4.0<< <1,000 0.87 58 5.0 G1-25 Isopropyl citrate 120  4.0<< 230 1.56 <45 4.8 F 1-26 Diisostearylmalate 450  4.0<< 640 0.28 <45 3.3 F 1-27 UNIOL PB1000R 70 5.5 1000 0.40<45 2.5 F 1-28 UNIOL D-250 20 4.0<< 250 <45 3.8 G 1-29 UNIOL D-400 304.0<< 400 0.76 <45 4.8 G 1-30 UNIOL D-700 50 34.6 700 0.58 <45 4.8 G1-31 UNIOL D-1000 70 26.7 1,000 0.51 <45 3.8 F 1-32 UNIOL D-1200 90 16.21,160 0.48 <45 3.0 F 1-33 UNIOL D-2000 160  2,030 <45 P 1-34 UNIOLD-3000 0.6 3,000 0.39 <45 3.0 P 1-35 UNIOL D-4000 450  0.5 4,000 0.38<45 2.5 P 1-36 PEG 1500 120  4.0<< 1,500-1,600 0.78 40 5.5 P 1-37WILBRITE CP9 120  0.6 1,150 0.21 35 6.8 P 1-38 UNILUBE MS-70K 50 2.81,140 0.30 <−10 1.5 F 1-39 NONION S-6 65 4.0<< 880 0.44 37 G 1-40UNILUBE 5TP-300KB 310  3.9 4,130 0.39 <45 2.0 P 1-41 WILBRITE s753 120 27.3 960 0.67 −5 3.5 F 1-42 UNIOL TG-330 30 330 1.27 <45 G 1-43 UNIOLTG-1000 100  21.2 1,000 0.61 <45 3.5 G 1-44 UNIOL TG-3000 230  4.3 3,0000.42 <45 1.0 P 1-45 UNIOL TG-4000 300  2.4 4,000 0.40 <45 2.0 P 1-46UNILUBE DGP-700 200  4.0<< 700 0.91 <0 3.5 F 1-47 UNIOX HC60 1150  3,5700.46 33 P 1-48 Vaseline  80<< 0.0 <1,000 0.00 55 4.0 P 1-49 None — — — —— 7.5 G *High viscosity, unmeasurable.

With sanitary napkin No. 1-49, which had no blood slipping agent, thesurface residue rate A was 7.5 mass %, but with sanitary napkins No. 1-1to No. 1-21 wherein the kinematic viscosity and water holding percentagewere within the prescribed ranges, the surface residue rate A was 2.5mass % or lower.

With sanitary napkins No. 1-1 to No. 1-21, it was observed that thehorse EDTA blood that was dropped onto the ridges of the top sheet sliddown from the ridges into the furrows, and was rapidly absorbed from thefurrows into the absorbent body. However, with sanitary napkin No. 1-49which had no blood slipping agent, the dropped horse EDTA blood did notslip down into the furrows but slowly dripped down into the furrows,most of it remaining on the ridges of the top sheet. Also, with theabsorbent articles with high a water holding percentage, as with No.1-30, for example, the horse EDTA blood that was dropped onto the ridgesof the top sheet did not slip down into the furrows but slowly drippedwhile partially remaining on the top sheet, and a portion thereofremained on the ridges.

This suggests that sanitary napkins No. 1-1 to No. 1-21 allow rapidmigration of menstrual blood from the top sheet into the absorbent body,when a large amount of menstrual blood has reached the top sheet atonce.

Next, several volunteer subjects were asked to wear sanitary napkinsNos. 1-1 to 1-49, and most of the obtained responses indicated that withthe sanitary napkins comprising blood slipping agents Nos. 1-1 to 1-21,the top sheets had no sticky feel and the top sheets were smooth, evenafter absorption of menstrual blood.

For this test example there was used a top sheet having a ridge-furrowstructure produced by the method described in Japanese Unexamined PatentPublication No. 2008-2034, but the blood slipping agent exhibits thesame blood slipping effect when using a top sheet having a ridge-furrowstructure produced by a different method, or when using a top sheethaving an irregular structure other than a ridge-furrow structure, andcan presumably cause menstrual blood to rapidly migrate from the topsheet into the absorbent body (see Test Example 8).

Test Example 3 Menstrual Blood Surface Residue Rate B, with Absorptionof Small Amount of Blood

A test was conducted to evaluate the absorption property of a sanitarynapkin after absorption of a small amount of blood.

There were prepared a top sheet, formed of a hydrophilic agent-treatedair-through nonwoven fabric (composite fiber composed of polyester andpolyethylene terephthalate, basis weight: 35 g/m²) (hereunder alsoreferred to as “top sheet with ridge-furrows”), a second sheet formed ofan air-through nonwoven fabric (composite fibers composed of polyesterand polyethylene terephthalate, basis weight: 30 g/m²), an absorbentbody comprising pulp (basis weight: 150 to 450 g/m², increased at thecenter section), an acrylic super-absorbent polymer (basis weight: 15g/m²) and tissue as a core wrap, a water-repellent agent-treated sidesheet, and a back sheet composed of a polyethylene film.

The top sheet was a top sheet produced by the method described inJapanese Unexamined Patent Publication No. 2008-2034, having aridge-furrow structure, with a ridge thickness of approximately 1.5 mmand a furrow thickness of approximately 0.4 mm, and the pitch of theridge-furrow structure (ridge width+furrow width) was approximately 4 mmand open holes were formed in the furrows at an open area ofapproximately 15%.

UNISTAR H-408BRS (product of NOF Corp., tetraester of pentaerythritoland fatty acid) was selected as the blood slipping agent, and it wascoated onto the skin contact surface (ridge-furrow side) of the topsheet from a control seam HMA gun at room temperature, to a basis weightof 5.0 g/m². With an electron microscope it was confirmed that theH-408BRS was adhering onto the fiber surfaces as fine particulates.

A back sheet, an absorbent body, a second sheet, and a top sheet withthe ridge-furrow side facing upward, were stacked in that order to formsanitary napkin No. 2-1(i).

A sanitary napkin No. 2-1(ii) was formed in the same manner as thesanitary napkin No. 2-1(i), except that the top sheet was changed to atop sheet formed of a flat hydrophilic agent-treated air-throughnonwoven fabric (composite fiber composed of polyester and polyethyleneterephthalate, basis weight: 35 g/m²), without a ridge-furrow structure(hereunder also referred to as “flat top sheet”).

Sanitary napkins No. 2-2(i) to No. 2-11(i) and No. 2-2(ii) to No.2-11(ii) were produced, changing the blood slipping agent from UNISTARH-408BRS to the ones listed in Table 3. Each blood slipping agent wasused directly, when it was liquid at room temperature, or when the bloodslipping agent was solid at room temperature it was heated to itsmelting point+20° C., and then a control seam HMA gun was used foratomization of the blood slipping agent and coating onto the skincontact surface of the top sheet to a basis weight of about 5 g/m².

The blood slipping agent was coated over essentially the entire skincontact surface of the top sheet, and on both the ridges and furrows ofthe top sheets with a ridge-furrow structure.

[Test Methods]

After measuring the mass W₄ (g) of the top sheet (the weight of the topsheet before the test), approximately 0.25 g (2 drops) of horse EDTAblood at 37±1° C. was added dropwise through a pipette, on the top sheetat the center in the lengthwise direction and widthwise direction of theabsorbent article. The horse EDTA blood was dropped onto the top partsof the ridges, in the top sheets with ridge-furrows.

At 30 seconds after dropping, the top sheet was taken off, the mass W₅(g) (weight of top sheet after the test) was measured and the “surfaceresidue rate B (mass %)” was calculated by the following formula.

Surface residue rate B(mass %)=100×(W ₅(g)−W ₄(g))/W ₆(g)

W₆ (g) is the weight of the dropped horse EDTA blood, calculated fromthe weight of the pipette before and after dropping.

The results are shown in Table 3 below.

TABLE 3 Surface residue rate B (mass %) Top sheet with Flat top No.Blood slipping agent ridge-furrows sheet 2-1 H-408 BRS 4% 32% 2-2PANACET 810S 8% 40% 2-3 Capric acid diglyceride 8% 24% 2-4 COMPOL BL 4%32% 2-5 Tributyl O-acetylcitrate 8% 44% 2-6 Dioctyl adipate 8% 32% 2-7ELECTOL WE40 8% 24% 2-8 UNIOL PB500 4% 68% 2-9 PARLEAM 6 4% 100%  2-10UNIOL D-250 16%  48% 2-11 None 28%  28%

Table 3 shows that when the blood slipping agent was H-408BRS, PANACET810S, capric acid diglyceride, COMPOL BL, tributyl O-acetylcitrate,dioctyl adipate, ELECTOL WE40, UNIOL PB500 or PARLEAM 6, the surfaceresidue rate B of the top sheet with ridge-furrows was low. Thissuggests that blood slipping agents having the prescribed propertiescause rapid migration of small amounts of blood from the ridges to thefurrows and into the absorbent body.

For this test example there was used a top sheet having a ridge-furrowstructure produced by the method described in Japanese Unexamined PatentPublication No. 2008-2034, but the blood slipping agent exhibits thesame blood slipping effect when using a top sheet having a ridge-furrowstructure produced by a different method, or when using a top sheethaving an irregular structure other than a ridge-furrow structure, andcan presumably cause menstrual blood to rapidly migrate from the topsheet into the absorbent body (see Test Example 8).

Test Example 4 Viscosity of Blood Containing Blood Slipping Agent

The viscosity of the blood slipping agent-containing blood was measuredusing a Rheometric Expansion System ARES (Rheometric Scientific, Inc.).After adding 2 mass % of PANACET 810s to horse defibrinated blood, themixture was gently agitated to form a sample, the sample was placed on a50 mm-diameter parallel plate, with a gap of 100 μm, and the viscositywas measured at 37±0.5° C. The sample was not subjected to a uniformshear rate, due to the parallel plate, but the average shear rateindicated by the device was 10 s⁻¹.

The viscosity of the horse defibrinated blood containing 2 mass %PANACET 810s was 5.9 mPa·s, while the viscosity of the horsedefibrinated blood containing no blood slipping agent was 50.4 mPa·s.Thus, the horse defibrinated blood containing 2 mass % PANACET 810sclearly had an approximately 90% lower viscosity than the bloodcontaining no blood slipping agent.

It is known that blood contains components, such as blood cells and hasa thixotropic nature, and it is believed that the blood slipping agentof the present disclosure has an effect of lowering the viscosity ofblood, such as menstrual blood in the low viscosity range. Lowering theblood viscosity presumably allows absorbed menstrual blood to moreeasily migrate rapidly from the top sheet to the absorbent body.

Test Example 5 Photomicrograph of Blood Slipping Agent-Containing Blood

Menstrual blood was sampled from healthy volunteers onto food storagewrap film, and PANACET 810s dispersed in a 10-fold mass ofphosphate-buffered saline was added to a portion thereof to a PANACET810s concentration of 1 mass %. The menstrual blood was dropped onto aslide glass, a cover glass was placed thereover, and the state of theerythrocytes was observed with an optical microscope. A photomicrographof menstrual blood containing no blood slipping agent is shown in FIG.7( a), and a photomicrograph of menstrual blood containing PANACET 810sis shown in FIG. 7( b).

As shown in FIG. 7, the erythrocytes formed aggregates, including arouleaux structure, in the menstrual blood containing no blood slippingagent, while the erythrocytes were stably dispersed in the menstrualblood containing PANACET 810s. This suggests that the blood slippingagent has the function of stabilizing erythrocytes in blood.

Test Example 6 Surface Tension of Blood Containing Blood Slipping Agent

The surface tension of blood containing a blood slipping agent wasmeasured by the pendant drop method, using a Drop Master500 contactangle meter by Kyowa Interface Science Co., Ltd. The surface tension wasmeasured after adding a prescribed amount of blood slipping agent tosheep defibrinated blood, and thoroughly shaking.

The measurement was accomplished automatically with the apparatus, andthe surface tension γ was determined by the following formula (see FIG.8).

γ=g×ρ×(de)²×1/H

g: Gravitational constant1/H: Correction factor determined from ds/de

ρ: Density

de: Maximum diameterds: Diameter at location of increase by de from dropping edge

The density ρ was measured at the temperatures listed in Table 4,according to JIS K 2249-1995, “Density test methods anddensity/mass/volume conversion tables”, 5. Vibrating density testmethod.

The measurement was accomplished using a DA-505 by Kyoto ElectronicsCo., Ltd.

The results are shown in Table 4 below.

TABLE 4 Measuring Surface Blood slipping agent temperature tension No.Type Amount (mass %) (° C.) (mN/m) 1 — — 35 62.1 2 PANACET 810s 0.01 3561.5 3 0.05 35 58.2 4 0.10 35 51.2 5 ELECTOL WE20 0.10 35 58.8 6 PARLEAM6 0.10 35 57.5 7 — — 50 56.3 8 WILBRITE cp9 0.10 50 49.1

Based on Table 4 it is seen that the blood slipping agent has an effectof lowering the surface tension of blood.

Lowering the surface tension of blood presumably allows absorbed bloodto rapidly migrate from the top sheet to the absorbent body, withoutbeing retained between the top sheet fibers.

Test Example 7 (1) Preparation of Samples A1-C1 and A2-C2

Three different commercially available sanitary napkins A to C wereprepared.

Sanitary napkin A (Sofy Hadaomoi by Unicharm Corp.) has a top sheet withan irregular structure formed on the skin contact surface (air-throughnonwoven fabric composed of PET/HDPE core-sheath composite fibers, basisweight: 35 g/m²) as a liquid-permeable layer, and a second sheetsituated between the top sheet and the absorbent body (air-throughnonwoven fabric composed of PET/HDPE core-sheath composite fibers, basisweight: 38 g/m²). The irregular structure formed on the skin contactsurface of the top sheet was a ridge-furrow structure formed by themethod described in Japanese Unexamined Patent Publication No.2008-2034, the thickness of the ridges being approximately 1.5 mm, thethickness of the furrows being approximately 0.4 mm, the pitch of theridge-furrow structure (ridge width+furrow width) being approximately 4mm and the open area of the open holes formed in the furrows beingapproximately 15%.

The sanitary napkin B used was “Laurier F” by Kao Corp. Sanitary napkin1 had a top sheet with an irregular structure formed on the skin contactsurface, as a liquid-permeable layer.

The sanitary napkin C used was “Laurier Speed Plus” by Kao Corp.Sanitary napkin C had a top sheet with an irregular structure formed onthe skin contact surface, as a liquid-permeable layer.

The skin contact surfaces of sanitary napkins A to C were coated with ablood slipping agent (triglyceride) to produce samples A1 to C1.Separately, sanitary napkins A to C, not coated with a blood slippingagent, were prepared as samples A2 to C2. The coating basis weight ofthe blood slipping agent was 10 g/m² for sample A1, 16 g/m² for sampleB1 and 57.6 g/m² for sample C1.

(2) Measurement of Rewetting Amount and Absorbent Body Migration Rate[Test Methods]

An acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40mm×10 mm hole opened at the center) was placed on the skin contactsurface of each sample, and 3 mL of horse EDTA blood at 37±1° C.(obtained by adding ethylenediaminetetraacetic acid (EDTA) to horseblood to prevent coagulation) was dropped through the hole using apipette (first time), and after 1 minute, 3 mL of horse EDTA blood at37±1° C. was again added dropwise through the acrylic board hole with apipette (second time). The dropping rate was 90 mL/min.

After the second dropping of blood, the acrylic board was immediatelyremoved and filter paper (Qualitative filter paper No. 2, product ofAdvantech Toyo, Inc., 50 mm×35 mm) was placed on the location where theblood had been dropped, and then a weight was placed thereover to apressure of 30 g/cm². After 1 minute, the filter paper was removed andthe rewetting amount (weight of filter paper after test—weight of filterpaper before test) was calculated.

Separately from evaluation of the rewetting amount, the migration timeof blood from the liquid-permeable layer into the absorbent body afterthe second dropping of the blood was measured, and was recorded as theabsorbent body migration rate (drain time). The absorbent body migrationrate is the time from introduction of blood into the liquid-permeablelayer until the redness of the blood is no longer visible on the surfaceand interior of the liquid-permeable layer.

[Results]

The rewetting amount of sample A1 was 0.05 g and the absorbent bodymigration rate was 8 seconds, while the rewetting amount of sample A2was 1.06 g and the absorbent body migration rate was longer than 60seconds.

The rewetting amount of sample B1 was 0.92 g and the absorbent bodymigration rate was 27 seconds, while the rewetting amount of sample B2was 1.47 g and the absorbent body migration rate was longer than 60seconds.

The rewetting amount of sample C1 was 0.61 g and the absorbent bodymigration rate was 28 seconds, while the rewetting amount of sample C2was 0.60 g and the absorbent body migration rate was longer than 60seconds.

With sample A1, the rewetting amount was notably reduced compared tosample A2, and the absorbent body migration rate was notably increased.This suggests that the function and effect of the blood slipping agentwere effectively exhibited with sample 1A.

In contrast, the rewetting amount was reduced and the absorbent bodymigration rate was increased with sample B1 compared to sample B2,although the amount of increase in the absorbent body migration rate wasnot as notable as with sample A1. This suggests that the function andeffect of the blood slipping agent were not as effectively exhibitedwith sample B1 compared to sample A1.

Also, the absorbent body migration rate was increased with sample C1compared to sample C2, although the amount of increase in the absorbentbody migration rate was not as notable as with sample A1. The rewettingamount was unchanged with sample C1 compared to sample C2. This suggeststhat the function and effect of the blood slipping agent were not aseffectively exhibited with sample C1 compared to sample A1.

The cause of the lack of an effective function and effect of the bloodslipping agent with samples B1 and C1 was therefore examined.

With sample A1, in the liquid-permeable layer, the basis weight was 35g/m² and the thickness was 0.8 mm on the upper layer (top sheet) whilethe basis weight was 38 g/m² and the thickness was 0.7 mm on the lowerlayer (second sheet), and the density of the upper layer was 0.04 g/cm²while the density of the lower layer was 0.06 g/cm³.

In contrast, in the liquid-permeable layer of sample B1, the basisweight was 30 g/m² and the thickness was 0.9 mm on the upper layer whilethe basis weight was 38 g/m² and the thickness was 0.3 mm on the lowerlayer, and the density of the upper layer was 0.03 g/cm² while thedensity of the lower layer was 0.15 g/cm².

Also, in the liquid-permeable layer of sample C1, the basis weight was24.5 g/m² and the thickness was 0.5 mm on the upper layer while thebasis weight was 30 g/m² and the thickness was 0.3 mm on the lowerlayer, and the density of the upper layer was 0.05 g/cm² while thedensity of the lower layer was 0.12 g/cm².

The densities of the upper layers were not significantly differentbetween samples A1 to C1, but the densities of the lower layers weresignificantly increased in samples B1 and C1 compared to sample A1. Thissuggests that the function and effect of the blood slipping agent areaffected by the densities of the upper layer and the lower layer.Specifically, it suggests that if the density of the lower layer isgreater than the density of the upper layer, the density of the lowerlayer being 0.1 g/cm² or less and the density of the upper layer being0.05 g/cm² or less, then the function and effect of the blood slippingagent can be effectively exhibited.

Test Example 8 (1) Preparation of Samples D1 and D2

A laminated sheet was prepared having a non-heat-shrinkable fiber layer(basis weight: 15 g/m²) and a heat-shrinkable fiber layer (basis weight:15 g/m²) for the upper layer and lower layer, respectively. Thenon-heat-shrinkable fiber layer was a web having a content of PET/PEcore-sheath composite fibers (3.3 dtex×51 mm, 4% titanium oxide contentin core) of 100 mass %, and the heat-shrinkable fiber layer (latentcrimping fiber layer) was a web having a content of coPP (PPcopolymer/PP side-by-side composite fibers (2.2 dtex×51 mm) of 20 mass %and a content of PET/PE core-sheath composite fibers (2.2 dtex×51 mm, 4%titanium oxide content in core) of 80 mass %. Both fibers were subjectedto hydrophilicizing treatment with a surfactant.

The laminated sheet was subjected to heat embossing treatment from thenon-heat-shrinkable fiber layer side, to form a heat embossed sectionwhere the non-heat-shrinkable fiber layer and heat-shrinkable fiberlayer were integrated. For the heat embossing treatment there was usedan embossing roll having a plurality of projections arranged in a zigzagfashion. The sizes and arranged spacing of the projections of theembossing roll were as shown in FIG. 9 (partially enlarged plan view ofembossing roll), and the heights were 1 mm. The treatment temperaturefor the heat embossing treatment was 130° C., the treatment time was 1second and the pressure was 15 kgf/mm².

Following heat embossing treatment, a floating dryer was used for heattreatment of the laminated sheet, producing heat stretching of theheat-extendable fiber, heat shrinkage of the heat-shrinkable fiber andheat fusion between the fibers. The treatment temperature for the heattreatment was 133° C. to 135° C., the wind speed was 5 m/sec and theline speed was 5 m/min. The area shrinkage factor of the laminated sheetafter heat treatment was 50% in the MD direction and 30% in the CDdirection.

Thus, a top sheet having an irregular structure formed on the skincontact surface was prepared, and the top sheet was used to produce asanitary napkin (the absorbent body comprising pulp at a basis weight of250 g/m², and the interface between the top sheet and the absorbent bodybeing joined with a hot-melt adhesive at a basis weight of a 5 g/m²),coating a blood slipping agent (triglyceride) on the skin contactsurface of the top sheet at a basis weight of 3 g/m². A blood slippingagent-coated article was used as sample D1, and a non-blood slippingagent-coated article was used as sample D2.

(2) Measurement of Penetration Time, Absorbent Body-Migration Time(Drain Time) and Rewetting Rate [Test Methods]

An acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40mm×10 mm hole opened at the center) was placed on the skin contactsurface of each sample, and 3 mL of horse EDTA blood at 37±1° C.(obtained by adding ethylenediaminetetraacetic acid (EDTA) to horseblood to prevent coagulation) was dropped through the hole using apipette (first time), and after 1 minute, 3 mL of horse EDTA blood at37±1° C. was again added dropwise through the acrylic board hole with apipette (second time). The dropping rate was 90 mL/min. The time fromeach dropping until the horse blood retained in the acrylic board holedisappeared, was recorded as the penetration time (sec), while the timeuntil the horse blood disappeared from the surface and interior of thetop sheet (the time until blood redness was no longer visible) wasmeasured and recorded as the absorbent body migration rate (drain time)(sec).

After the second dropping of blood, the acrylic board was immediatelyremoved and 10 sheets of filter paper (Qualitative filter paper No. 2,product of Advantech Toyo, Inc., 50 mm×35 mm) were placed on thelocation where the blood had been dropped, and then a weight was placedthereover to a pressure of 30 g/cm². After 1 minute, the filter paperwas removed and the rewetting rate was calculated by the followingformula.

Rewetting rate (%)=100×(filter paper mass after test−initial filterpaper mass)/6

[Results]

With sample D1, the liquid permeation rate (1st time) was 2 seconds, theliquid permeation rate (2nd time) was 2.67 seconds, the absorbent bodymigration rate (1st time) was 12.42 seconds, the absorbent bodymigration rate (2nd time) was 27.78 seconds, and the rewetting rate was1.2%.

In contrast, with sample D2, the liquid permeation rate (1st time) was2.35 seconds, the liquid permeation rate (2nd time) was 2.48 seconds,the absorbent body migration rate (1st time) was 12.75 seconds, theabsorbent body migration rate (2nd time) was longer than 60 seconds, andthe rewetting rate was 4.3%.

This test example demonstrated that even when using a top sheet havingan irregular structure formed on the skin contact surface by heatstretching of the heat-extendable fibers and/or heat shrinkage of theheat-shrinkable fibers, it is possible for the blood slipping agent toexhibit a blood-slipping function and allow menstrual blood to rapidlymigrate from the top sheet into the absorbent body.

Test Example 9 (1) Preparation of Samples E1 and E2

A laminated sheet was prepared having a non-heat-shrinkable fiber layer(basis weight: 15 g/m²) and a heat-shrinkable fiber layer (basis weight:15 g/m²) for the upper layer and lower layer, respectively. Thenon-heat-shrinkable fiber layer was a web having a content of PET/PEcore-sheath composite fibers (3.3 dtex×51 mm, 4% titanium oxide contentin core) of 100 mass %, and the heat-shrinkable fiber layer (latentcrimping fiber layer) was a web having a content of coPP (PPcopolymer/PP side-by-side composite fibers (2.2 dtex×51 mm) of 20 mass %and a content of PET/PE core-sheath composite fibers (2.2 dtex×44 mm, 4%titanium oxide content in core) of 80 mass %. Both fibers were subjectedto hydrophilicizing treatment with a surfactant.

This was followed by embossing treatment and heat treatment in the samemanner as Test Example 8. The basis weight before heat treatment was 35g/m², and the basis weight after heat treatment was 170 g/m². Thus, atop sheet having an irregular structure formed on the skin contactsurface was prepared (the absorbent body comprising pulp at a basisweight of 250 g/m², the interface between the top sheet and theabsorbent body being joined with a hot-melt adhesive at a basis weightof a 5 g/m²), and the top sheet was used to produce a sanitary napkin,coating a blood slipping agent (triglyceride) on the skin contactsurface of the top sheet at a basis weight of 3 g/m². A blood slippingagent-coated article was used as sample E1, and a non-blood slippingagent-coated article was used as sample E2.

(2) Preparation of Samples F1 and F2

Samples F1 and F2 were fabricated in the same manner as samples E1 andE2, except that the mass mixing ratio in the heat-shrinkable fiber layer(latent crimping fiber layer) was changed to coPP (PP copolymer)/PPside-by-side composite fibers: PET/PE core-sheath composite fibers=5:5.The basis weight before heat treatment was 17.5 g/m², and the basisweight after heat treatment was 165 g/m².

(3) Measurement of Blood Residue Rate [Test Methods]

An acrylic board with an opened hole (200 mm×100 mm, 125 g, with a 40mm×10 mm hole opened at the center) was placed on the skin contactsurface of each sample, and 3 mL of horse EDTA blood at 37±1° C.(obtained by adding ethylenediaminetetraacetic acid (EDTA) to horseblood to prevent coagulation) was dropped through the hole using apipette (first time), and after 1 minute, 3 mL of horse EDTA blood at37±1° C. was again added dropwise through the acrylic board hole with apipette (second time). The dropping rate was 90 mL/min. After the secondblood dropping, it was allowed to stand for 1 minute and the bloodresidue rate was calculated by the following formula.

Blood residue rate (%)=100×(sample mass after test−initial samplemass)/6

[Results]

The blood residue rate was 17.3% for sample E1, 26.6% for sample E2,10.2% for sample F1 and 17.8% for sample F2.

This test example demonstrated that even when using a top sheet havingan irregular structure formed on the skin contact surface by heatshrinkage of the heat-shrinkable fibers, it is possible for the bloodslipping agent to exhibit a blood-slipping function and to allowmenstrual blood to rapidly migrate from the top sheet into the absorbentbody.

It was also shown that a greater amount of latent crimping fibersincreases the amount of blood residue. This is presumably because whencrimping of the latent crimping fibers becomes developed by heattreatment, the fibers form coils, thereby increasing the bloodretentivity. On the other hand, the blood slipping agent exhibits ablood slipping function, allowing menstrual blood to rapidly migratefrom the top sheet into the absorbent body before the blood becomes heldinside the coiled fibers.

Test Example 10 (1) Preparation of Samples G1 and G2

PET/PE core-sheath composite fibers (3.3 dtex×51 mm, 4% titanium oxidecontent in core) were used to form a heat-extendable fiber layer. Theheat-extendable fiber layer was a web with a basis weight of 44 g/m² anda thickness of 1.6 mm. The web was subjected to embossing at a treatmenttemperature of 130° C., a pressing time of 1 second and a pressure of 15kgf/mm². For this there was used an emboss pattern havingrhomboid-shaped projections with 9 mm sides and 15 mm long diagonals,arranged at spacings of 1 mm. Projections with widths of 1 mm wereformed on the web surface by sections with spacings of 1 mm.

This was followed by air-through treatment with a hot air drier (linespeed: 5 m/min, wind speed: 1.5 m/sec, temperature: 135° C.), to formthe web into a nonwoven fabric. Thus, a top sheet having an irregularstructure formed on the skin contact surface was prepared, and the topsheet was used to produce a sanitary napkin (the absorbent bodycomprising pulp at a basis weight of 250 g/m², and the interface betweenthe top sheet and the absorbent body being joined with a hot-meltadhesive at a basis weight of a 5 g/m²), coating a blood slipping agent(triglyceride) on the skin contact surface of the top sheet at a basisweight of 3 g/m². A blood slipping agent-coated article was used assample G1, and a non-blood slipping agent-coated article was used assample G2.

(2) Preparation of Samples H1 and H2

PET/PE core-sheath composite fibers (3.3 dtex×51 mm, 4% titanium oxidecontent in core) were used to form a non-heat-extendable fiber layer.The heat-extendable fiber layer was a web with a basis weight of 44 g/m²and a thickness of 1.2 mm. The web was used to prepare samples H1 and H2in the same manner as samples G1 and G2.

(3) Measurement of Penetration Time, Absorbent Body-Migration Time(Drain Time) and Rewetting Rate

The penetration time, absorbent body-migration time (drain time) andrewetting rate were measured in the same manner as Test Example 8.

With sample G1, the liquid permeation rate (1st time) was 2 seconds, theliquid permeation rate (2nd time) was 2.59 seconds, the absorbent bodymigration rate (1st time) was 5.29 seconds, the absorbent body migrationrate (2nd time) was 15.89 seconds, and the rewetting rate was 8.9%.

With sample G2, the liquid permeation rate (1st time) was 2 seconds, theliquid permeation rate (2nd time) was 2.84 seconds, the absorbent bodymigration rate (1st time) was longer than 60 seconds, the absorbent bodymigration rate (2nd time) was longer than 60 seconds, and the rewettingrate was 17.2%.

With sample H1, the liquid permeation rate (1st time) was 2 seconds, theliquid permeation rate (2nd time) was 2.75 seconds, the absorbent bodymigration rate (1st time) was 12.11 seconds, the absorbent bodymigration rate (2nd time) was 40 seconds, and the rewetting rate was11.7%.

With sample H2, the liquid permeation rate (1st time) was 2 seconds, theliquid permeation rate (2nd time) was 3.19 seconds, the absorbent bodymigration rate (1st time) was longer than 60 seconds, the absorbent bodymigration rate (2nd time) was longer than 60 seconds, and the rewettingrate was 20%.

This test example demonstrated that even when using a top sheet havingan irregular structure formed on the skin contact surface by heatstretching of the heat-extendable fibers, it is possible for the bloodslipping agent to exhibit a blood-slipping function and to allowmenstrual blood to rapidly migrate from the top sheet into the absorbentbody.

Also, it is presumed that because heat stretching of the heat-extendablefibers increases the bulk and lowers the density, the system usingheat-extendable fibers provided more satisfactory results than thesystem using non-heat-extendable fibers. Presumably this is because theclosed regions surrounded by embossed sections readily extend in thethickness direction during extension of heat-extendable fibers.

REFERENCE SIGNS LIST

-   1 Sanitary napkin (absorbent article)-   2 Top sheet (liquid-permeable layer)-   3 Back sheet (liquid-impermeable layer)-   4 Absorbent body-   5 Compressed section (joining section)-   8 Projection-   9 Recess

1. An absorbent article comprising a liquid-permeable layer, aliquid-impermeable layer and an absorbent body situated between theliquid-permeable layer and the liquid-impermeable layer, wherein theliquid-permeable layer has a first layer with a skin contact surface anda non-skin contact surface and a second layer situated on the non-skincontact surface side of the first layer, the second layer is a layerformed by heat shrinkage of a heat-shrinkable fiber layer and the firstlayer is a layer formed by deformation of a non-heat-shrinkable fiberlayer which is partially joined to the heat-shrinkable fiber layer by ajoining section, by heat shrinkage of the heat-shrinkable fiber layer, aprojection bulges out on the skin contact surface side, produced bydeformation of the non-heat-shrinkable fiber layer, are formed at leastin the excretory opening contact region on the skin contact surface, andat least the projection of the excretory opening contact region iscoated with a blood slipping agent having a 40° C. kinematic viscosityof 0.01 to 80 mm²/s, a water holding percentage of 0.01 to 4.0 mass %and a weight-average molecular weight of less than 1,000.
 2. Theabsorbent article according to claim 1, wherein the density of thesecond layer is greater than the density of the first layer.
 3. Theabsorbent article according to claim 2, wherein the density of thesecond layer is 0.1 g/cm³ or less.
 4. The absorbent article according toclaim 2, wherein the density of the first layer is 0.05 g/cm³ or less.5. The absorbent article according to claim 1, wherein the joiningsection is a compressed section in which the non-heat-shrinkable fiberlayer and the heat-shrinkable fiber layer are integrated in thethickness direction.
 6. The absorbent article according to claim 1,wherein the IOB of the blood slipping agent is 0.00 to 0.60.
 7. Theabsorbent article according to claim 1, wherein the blood slipping agentis selected from the group consisting of the following items (i)-(iii),and any combination thereof: (i) a hydrocarbon; (ii) a compound having(ii-1) a hydrocarbon moiety, and (ii-2) one or more, same or differentgroups selected from the group consisting of carbonyl group (—CO—) andoxy group (—O—) inserted between a C—C single bond of the hydrocarbonmoiety; and (iii) a compound having (iii-1) a hydrocarbon moiety,(iii-2) one or more, same or different groups selected from the groupconsisting of carbonyl group (—CO—) and oxy group (—O—) inserted betweena C—C single bond of the hydrocarbon moiety, and (iii-3) one or more,same or different groups selected from the group consisting of carboxylgroup (—COOH) and hydroxyl group (—OH) substituting a hydrogen of thehydrocarbon moiety; with the proviso that when 2 or more oxy groups areinserted in the compound of (ii) or (iii), the oxy groups are notadjacent.
 8. The absorbent article according to claim 1, wherein theblood slipping agent is selected from the group consisting of thefollowing items (i′)-(iii′), and any combination thereof: (i′) ahydrocarbon; (ii′) a compound having (ii′-1) a hydrocarbon moiety, and(ii′-2) one or more, same or different bonds selected from the groupconsisting of carbonyl bond (—CO—), ester bond (—COO—), carbonate bond(—OCOO—), and ether bond (—O—) inserted between a C—C single bond of thehydrocarbon moiety; and (iii′) a compound having (iii′-1) a hydrocarbonmoiety, (iii′-2) one or more, same or different bonds selected from thegroup consisting of carbonyl bond (—CO—), ester bond (—COO—), carbonatebond (—OCOO—), and ether bond (—O—) inserted between a C—C single bondof the hydrocarbon moiety, and (iii′-3) one or more, same or differentgroups selected from the group consisting of carboxyl group (—COOH) andhydroxyl group (—OH) substituting a hydrogen on the hydrocarbon moiety;with the proviso that when 2 or more same or different bonds areinserted in the compound of (ii) or (iii′), the bonds are not adjacent.9. The absorbent article according to claim 1, wherein the bloodslipping agent is selected from the group consisting of the followingitems (A)-(F), and any combination thereof: (A) an ester of (A1) acompound having a chain hydrocarbon moiety and 2-4 hydroxyl groupssubstituting hydrogens on the chain hydrocarbon moiety, and (A2) acompound having a chain hydrocarbon moiety and 1 carboxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety; (B) an ether of(B1) a compound having a chain hydrocarbon moiety and 2-4 hydroxylgroups substituting hydrogens on the chain hydrocarbon moiety and (B2) acompound having a chain hydrocarbon moiety and 1 hydroxyl groupsubstituting a hydrogen on the chain hydrocarbon moiety; (C) an ester of(C1) a carboxylic acid, hydroxy acid, alkoxy acid or oxoacid comprisinga chain hydrocarbon moiety and 2-4 carboxyl groups substitutinghydrogens on the chain hydrocarbon moiety and (C2) a compound having achain hydrocarbon moiety and 1 hydroxyl group substituting a hydrogen onthe chain hydrocarbon moiety; (D) a compound having a chain hydrocarbonmoiety and one bond selected from the group consisting of an ether bond(—O—), carbonyl bond (—CO—), ester bond (—COO—) and carbonate bond(—OCOO—) inserted between a C—C single bond of the chain hydrocarbonmoiety; (E) a polyoxy C₃-C₆ alkylene glycol, or alkyl ester or alkylether thereof; and (F) a chain hydrocarbon.
 10. The absorbent articleaccording to claim 1, wherein the blood slipping agent is selected fromthe group consisting of (a₁) an ester of a chain hydrocarbon tetraol andat least one fatty acid, (a₂) an ester of a chain hydrocarbon triol andat least one fatty acid, (a₃) an ester of a chain hydrocarbon diol andat least one fatty acid, (b₁) an ether of a chain hydrocarbon tetraoland at least one aliphatic monohydric alcohol, (b₂) an ether of a chainhydrocarbon triol and at least one aliphatic monohydric alcohol, (b₃) anether of a chain hydrocarbon diol and at least one aliphatic monohydricalcohol, (c₁) an ester of a chain hydrocarbon tetracarboxylic acid,hydroxy acid, alkoxy acid or oxoacid with 4 carboxyl groups, and atleast one aliphatic monohydric alcohol, (c₂) an ester of a chainhydrocarbon tricarboxylic acid, hydroxy acid, alkoxy acid or oxoacidwith 3 carboxyl groups, and at least one aliphatic monohydric alcohol,(c₃) an ester of a chain hydrocarbon dicarboxylic acid, hydroxy acid,alkoxy acid or oxoacid with 2 carboxyl groups, and at least onealiphatic monohydric alcohol, (d₁) an ether of an aliphatic monohydricalcohol and an aliphatic monohydric alcohol, (d₂) a dialkyl ketone, (d₃)an ester of a fatty acid and an aliphatic monohydric alcohol, (d₄) adialkyl carbonate, (e₁) a polyoxy C₃-C₆ alkylene glycol, (e₂) an esterof a polyoxy C₃-C₆ alkylene glycol and at least one fatty acid, (e₃) anether of a polyoxy C₃-C₆ alkylene glycol and at least one aliphaticmonohydric alcohol, and (f₁) a chain alkane, and any combinationthereof.
 11. The absorbent article according to claim 1, wherein theblood slipping agent has a vapor pressure of 0.00 to 0.01 Pa at 1atmosphere, 40° C.